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General Astronomy >> General Observing and Astronomy

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drollere
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unlearning the constellations
      #5477666 - 10/18/12 08:15 PM

last night, bad seeing prompted me to tour the milky way with a binocular, something worth doing anyway at this time of the year.

i am reasonably familiar with the milky way large scale structure, and as i was indulging in my imaginative recognition of how far away the different star fields were, i realized that the constellations actually get in the way.

we all learn the constellations in our novice steps, and these ingrain certain asterisms in mind as if they are equally distant stars appearing at pretty much their absolute magnitudes. this is so far from the truth that it seems necessary to unlearn the constellations in order to make sense of the sky.

i've posted some animated gif images HERE that contrast apparent brightness, spatial distance and absolute magnitude of stars in the summer and winter milky way. the differences between the representations are pretty drastic.

thematically the distance image suggests the random scatter of stars; the absolute magnitude shows the clustering of OB and A types within the milky way plane. what's remarkable is that the visual patterns of the constellation asterisms have nothing to do with either. the puny brightness of vega, altair and arcturus, and the far brilliance of deneb and antares (or the whole of orion) are striking.

my sentiment is that astronomers generally spend too much attention on getting large aperture to see faint details in far galaxies, when there is a wealth of dense detail -- nebulae, galactic clusters, giant dust and molecular clouds, star clouds, layered features lying in different spiral arms -- that is available for study in our own galaxy, even with the naked eye. why is this so commonly ignored?

i think a large part of that has to do with the pinhole mentality of the catalog list and GOTO mount: we go about looking at specific objects that are only arcminutes wide, at best. the idea that a spacewalk eyepiece is *so* much better than a drinking straw eyepiece obscures the basic fact that they both show you a minuscule fragment of the celestial sphere. put that 17mm 100 $800 tele vue ethos in your 16" /4 dob and you get to see 0.0024% of the sky at any one time!

we piece together glimses of these pinhole samples of the sky as isolated features with nonsense pidgin arabic or cartoon character names, and call it "astronomy" with the absurdity of someone who has a pet name for every piece in a 100 or 1000 piece jigsaw puzzle but has never put the puzzle together to see what it represents. deep sky, double star, list chasing astronomers, we all fall into this trap. constellations only cement the delusion -- all those stars "go together" in a completely arbitrary patch of sky, even though the stars usually have nothing to do with each other and in our minds have only a hazy connection (if any) to the landscape they inhabit.

here's my puzzle: what to do? what is the most effective way to unlearn the constellations and reconnect the visible stars so that we can recognize similar distances or galactic regions? how might we learn the very simple distinction between population I and II stars in the general direction of the galactic pole? how can we learn to recognize at least a few major OB associations? what are the major landmarks -- orion, the hyades, the brightest near stars -- that give us some traction?

the problem seems so big that it's hard to know where or how to begin. it seems to me that binoculars, night vision scopes or the naked eye are the essential tools to work with ... but what books, software or atlases can assist? there is a very weak connection between concept renderings such as GALAXY MAP and the appearance of the galaxy with binocular or eyes.

my animated gifs may impress that visual brightness provides a very weak foothold onto the imaginative problem of seeing the big landscape of our home galaxy. perhaps we look at far away objects in isolated and tiny fields of view because ... it is just so much easier to do.


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GlennLeDrew
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Re: unlearning the constellations new [Re: drollere]
      #5478002 - 10/18/12 11:42 PM

Bruce,
You're doing pretty much exactly what I started out on about 20 years ago. And I'm still at it!

After hunting down many hundreds of DSOs, this began to get tiring. The next logical step was to strive for a more holistic understanding of the location, nature and kinematics of these objects, and how they are related within the scheme of the Galaxy.

By taking such an approach, one finds a *lot* to learn and see in our corner of the Galaxy. And no big light buckets are required; a binocular is quite adequate for much of this study.

Multitudes of dark clouds, scores of young stellar associations and star forming regions and the Gould Belt are some brand new territory for the observer looking to feel the excitement of fresh discoveries. And building up a mental 3-D map of all this stuff will transform the 'flat' dome of the sky into a dynamic ocean of space.


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magic612
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Re: unlearning the constellations new [Re: drollere]
      #5478004 - 10/18/12 11:42 PM

Bruce, that's an interesting question - or should I say, interesting questionS. I'm not sure I have any easy answers.

As to myself, I've found that I have been learning new things about the sky as I research for my weekly astronomy videos. I can't say I've made too many connections (yet) with respect to the specific objects you mentioned, except perhaps when I did a "zoom" towards Orion's belt stars in this video from April. I found it an interesting view to see how ALL of Orion's stars seem so bright, and yet are so different in distance. I'm not sure if that correlates to what you're getting at with regards to stellar associations though.

But the one area I have forced myself to "unlearn" and think about the sky in a larger, more macro-sense is with globular clusters. I started looking at WHERE they all are, in relation to the galactic center and galactic plane. It really is interesting when one starts to look at where these objects reside in relation to both the Milky Way in general - either side of it - and the concentration of them as well as the dispersion of them the further one goes from the galactic center.

I'm not sure if that's exactly what you're getting at, but I found it a fascinating way to look at the sky in a larger sense, despite the fact that the objects themselves are still small (from our perspective). So I guess that's my only "unlearning."


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drollere
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Re: unlearning the constellations new [Re: magic612]
      #5478172 - 10/19/12 01:56 AM

starting with the globulars is probably a very good strategy. that's how shapley deduced the location of the galaxy center, and the sun's distance from it.

i remember my surprise when i learned that the pleiades are actually much farther from us than the hyades -- they seem bright enough to be closer. maybe there is a selection of 50 or 100 stars that can be used as signposts to the distance and direction of specific features, in the way deneb is close to the root of the orion spiral arm.

glenn, i have enjoyed your interest in intergalactic clouds and milky way structure in some of your past posts. can you perhaps review your steps to a more holistic understanding, the big pieces that helped solidify the details?

i remember the first time i learned about barnard's loop, and the fact that the horsehead nebula and the great orion nebula, always photographed and described as separate objects, are actually parts of a single enormous feature. there must be dozens and dozens of similar connections to be made.


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Jon Isaacs
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Re: unlearning the constellations new [Re: drollere]
      #5478289 - 10/19/12 06:06 AM

Quote:

my sentiment is that astronomers generally spend too much attention on getting large aperture to see faint details in far galaxies, when there is a wealth of dense detail -- nebulae, galactic clusters, giant dust and molecular clouds, star clouds, layered features lying in different spiral arms -- that is available for study in our own galaxy, even with the naked eye. why is this so commonly ignored?

i think a large part of that has to do with the pinhole mentality of the catalog list and GOTO mount: we go about looking at specific objects that are only arcminutes wide, at best. the idea that a spacewalk eyepiece is *so* much better than a drinking straw eyepiece obscures the basic fact that they both show you a minuscule fragment of the celestial sphere. put that 17mm 100 $800 tele vue ethos in your 16" /4 dob and you get to see 0.0024% of the sky at any one time!




Bruce:

Some interesting stuff, translating the 2 dimensional views of the eyepiece to the 3 dimensional (ignoring time) views that science and careful measurement provides us. That is an integration of the senses with the intellect.

We all enjoy the sky in a different way... I very much enjoy just wandering around and seeing what I can see, figuring out what it is, learning something about it... I don't use GOTO, I view the constellations as part of the road map, sign posts to help me find my way from one part of the sky to another.

I am a big believer in using a telescope as an instrument of discovery rather than as tool to go down a list of objects... It's a different paradigm. I mostly work from the sky to the books rather than from the books to the sky. But I have to admit that I think in 2 dimensions...

At some point, one has to recognize what it is that draws one to this hobby... For me, it's not the science as much as it is the aesthetics, I just enjoy looking through a telescope/binoculars/naked eye at the night sky... It's just neat being out there under the night sky.

Binoculars are good but for me, a scope like the NP-101 with a nice eyepiece like the 31mm Nagler is better and even better is a collection of telescopes that provide different views on different scales... There is a lot of neat stuff to see... it's neat to look through big scopes, it's neat to look through small scopes and there is a lot to be learned doing both.

Jon


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magic612
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Re: unlearning the constellations new [Re: Jon Isaacs]
      #5478381 - 10/19/12 08:23 AM

Quote:

At some point, one has to recognize what it is that draws one to this hobby... For me, it's not the science as much as it is the aesthetics, I just enjoy looking through a telescope/binoculars/naked eye at the night sky... It's just neat being out there under the night sky.




Interesting that you say this, Jon. That also describes me to a tee. In some ways, I feel a bit "outside the norm" in that regard, but reading you say that, it also makes me wonder how many others feel the same way.

But I don't want to drag the thread off-topic either.


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Doc Willie
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Re: unlearning the constellations new [Re: Jon Isaacs]
      #5478418 - 10/19/12 09:09 AM

Quote:

. . .even better is a collection of telescopes that provide different views on different scales... There is a lot of neat stuff to see... it's neat to look through big scopes, it's neat to look through small scopes and there is a lot to be learned doing both.

Jon




My dream observatory would have room to have at least three scopes set up all the time -- a light bucket, and 8" SCT Go-to, and a refractor.


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Dennis_S253
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Re: unlearning the constellations new [Re: Doc Willie]
      #5478520 - 10/19/12 10:14 AM

I have been trying to stay away from this thread, but something keeps pulling me to it. I personally take it a little offensive with your so called "pinhole mentality". If it pleases someone to set up a scope and view the wonders of the sky then so be it.

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csa/montana
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Re: unlearning the constellations new [Re: Jon Isaacs]
      #5478540 - 10/19/12 10:27 AM

Quote:

We all enjoy the sky in a different way... I very much enjoy just wandering around and seeing what I can see, figuring out what it is, learning something about it... I don't use GOTO, I view the constellations as part of the road map, sign posts to help me find my way from one part of the sky to another.

I am a big believer in using a telescope as an instrument of discovery rather than as tool to go down a list of objects... It's a different paradigm. I mostly work from the sky to the books rather than from the books to the sky. But I have to admit that I think in 2 dimensions...

At some point, one has to recognize what it is that draws one to this hobby... For me, it's not the science as much as it is the aesthetics, I just enjoy looking through a telescope/binoculars/naked eye at the night sky... It's just neat being out there under the night sky.




Jon, we are kindred spirits in our viewing! I view exactly in the way you describe.

The main point is, yes; we all view the beautiful night skies in different ways. One person's way does not make another's wrong. The "pinhole mentality" is rather discouraging to us, that prefer to view the night sky thru our scopes.

My telescope has opened up a whole new, exciting world to me; I would not enjoy it nearly as much without my telescope; pinhole mentality? Maybe, but it sure is fulfilling to me. I love to put my 30ES in, and just wander all over the sky, stopping at something that looks interesting.

I take many breaks from the scope, & open up my camping chair, and lean back & just drink in the night sky; to me, the scope & just sitting in a chair looking up; is the best of both worlds. Again, there is no "right or wrong" way to view the night sky, as long as you enjoy it!


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Jon Isaacs
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Re: unlearning the constellations new [Re: csa/montana]
      #5478671 - 10/19/12 11:42 AM

Quote:

My telescope has opened up a whole new, exciting world to me; I would not enjoy it nearly as much without my telescope; pinhole mentality? Maybe, but it sure is fulfilling to me. I love to put my 30ES in, and just wander all over the sky, stopping at something that looks interesting.





Carol:

That hardly sounds like the pinhole mentality to me. Rather that is very much in line with the concept of a telescope being an instrument of discovery.

The "pinhole mentality" a 5 inch scope with a 1.25 focuser and a 1900mm focal length that requires GOTO to make it useable. It's driving nonstop the 143 miles from the Grand Canyon to the Betatakin Ruins at Navajo National Monument without taking the time to appreciate all the wonders in between.

What I suspect is that Bruce maybe moving away from an individual object oriented list based observing mentality to a universal the "whole sky is one big DSO" paradigm and adding an intellectual 3D aspect.

Myself, I just like looking. Beginners Mind, Zen Mind... "I ride my bicycle to ride my bicycle." I look through my telescope to look through my telescope.

Jon Isaacs


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csrlice12
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Re: unlearning the constellations new [Re: Jon Isaacs]
      #5478691 - 10/19/12 11:50 AM

"At some point, one has to recognize what it is that draws one to this hobby... For me, it's not the science as much as it is the aesthetics, I just enjoy looking through a telescope/binoculars/naked eye at the night sky... It's just neat being out there under the night sky."

Couldn't have said it any better.....


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Astrodj
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Re: unlearning the constellations new [Re: drollere]
      #5478728 - 10/19/12 12:17 PM

Bruce,

I imagine a planetarium program that could be told to show the naked eye sky from any location in or near the galaxy. It would be like having a virtual spaceship. One would quickly get lost if the program were so sophisticated as to able to put the reference point into light years per second motion.

I wouldn't mind heading out toward the Cone Nebula and tooling around for a while to see what the area looks like from other angles.

My interest in forming a mental picture of the actual 3D location of common celestial objects within our galaxy took
flight when I learned that the vast majority of what is visible to the naked eye is contained within a relatively small bubble of space with a radius of roughly 1500 parsecs, with us being in the center of the bubble.

Only 7,000 or so of the nearest AND brightest stars are visble to the unaided eye, mostly within that bubble, out of 2 or 3 hundred billion stars in the galaxy. Over half of either total are red dwarfs with only a scant few visible without optical aid, even the relatively near ones.

Looking toward the learned constellation of Saggitarius without optical aid, we can see (with a few exceptions) only about an eighth of the distance to the center of our galaxy. Same story along the galactic plane in the opposite direction towards the outer edge. Then there is the other entire half of the galaxy left to consider.

It's a lot to map, and I have only a very rudimentary knowledge of where the objects I can see actually are on that map so far, but I'm learning.

I too spend most of my time observing the "objects" in a telescope, because I enjoy it so much. But, I do make an effort to mentally place said object within our galaxy where it belongs, as best I can. Knowing what else is also in the locale of that object however, is another question that goes largely unanswered for me most of the time.


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csrlice12
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Re: unlearning the constellations new [Re: Astrodj]
      #5478744 - 10/19/12 12:25 PM

To someone somewhere else, our sun is just another star, maybe part of the handle to the whatchamacallit costellation.

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csrlice12
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Re: unlearning the constellations *DELETED* new [Re: Astrodj]
      #5478746 - 10/19/12 12:25 PM

Duplicate Post deleted by csa/montana

Edited by csa/montana (10/19/12 12:46 PM)


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bassplayer142
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Re: unlearning the constellations new [Re: csrlice12]
      #5478755 - 10/19/12 12:32 PM

I've found that getting a sense of depth works a lot better in dark skies. Unfortunately I don't have those. As far as distances of star fields, it seems safe to say that the dimmer it is the farther it is in general.

Next time I look at a good globular I'm going to try to visualize it three dimension-ally by thinking about star brightness and see what happens.


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Astrodj
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Re: unlearning the constellations new [Re: bassplayer142]
      #5478797 - 10/19/12 01:01 PM

One of the reasons I enjoy Burnham's Celestial Handbooks so much is I get a rough idea of the distances to many of the brighter stars, clusters, and nebulae. Combine that knowledge with the general direction of the object in the night sky and I can come up with an approximate placement within the galactic plane, reference our sun and it's location in the galaxy.

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Astrodj
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Re: unlearning the constellations new [Re: drollere]
      #5478909 - 10/19/12 02:13 PM

Quote:


we all learn the constellations in our novice steps, and these ingrain certain asterisms in mind as if they are equally distant stars appearing at pretty much their absolute magnitudes.




I think people who have been at this a while are aware that distance variations exist between stars of the constellation asterisms, star brightness is apparent not absolute, and that the groupings are line of sight. It is probably the rare individual that can look at a given constellation and recall from memory the different distances of even the brightest members, forming a mental 3D image. Sounds like maybe a good place to start actually.


Quote:


constellations only cement the delusion -- all those stars "go together" in a completely arbitrary patch of sky, even though the stars usually have nothing to do with each other and in our minds have only a hazy connection (if any) to the landscape they inhabit.




Well, they do have something in common. They lie in generally the same direction of the galaxy from us, which narrows down considerably their location in two dimensions. I agree with you that the landscape they each inhabit is something I remain largely unaware of without considerable legwork in the books. Even then it's pretty sketchy.

Quote:

perhaps we look at far away objects in isolated and tiny fields of view because ... it is just so much easier to do.




Personally, I do it because I enjoy the view, narrow as it may be. I also find the 3D reality of the bigger picture fascinating, and see no reason you can't be interested in primarily one or the other, or both.


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csrlice12
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Re: unlearning the constellations new [Re: Astrodj]
      #5478932 - 10/19/12 02:23 PM

and I know in my mind the sun doesn't set, it's the earth's rotation that is accounting for this phenomena; but that doesn't mean I don't appreaciate those beautiful sunsets....

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drollere
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Re: unlearning the constellations new [Re: Dennis_S253]
      #5479069 - 10/19/12 03:58 PM

Quote:

I have been trying to stay away from this thread, but something keeps pulling me to it. I personally take it a little offensive with your so called "pinhole mentality". If it pleases someone to set up a scope and view the wonders of the sky then so be it.




there are two ways to misinterpret a post, and you've done both.

first, imagine your view of the universe is that you are wearing opaque goggles, with a pinhole in them centered over your pupil. you can see out, but you can't see much. or imagine that you can only use your telescope with a single high powered eyepiece -- but your head is covered with a cloak and you can't look at the sky. how will you be able to perceive what is actually around you, or what the sky looks like "big picture"?

now pick up astronomy books. messier lists, herschel lists, double star lists, showcase objects, the burnham cabinet of curiosities ... where is there a book that tells you about the big picture, puts all these objects in context? besides crossan's "binocular astronomy", i can't think of one.

my point is: your view is limited by the *way* you are looking.

second, why is suggesting that people pay more attention to something mean they should *stop* paying attention to something else? or that paying attention to anything else is *wrong*?

my appeal was for some ideas to help make the big picture easier to see, to remember, to teach. for references to books that talk about the big picture. for concepts or signposts that make it easier to visualize. all that, because our galaxy is the biggest, brightest, most detailed, most resplendent galaxy it is possible for us to see ... no matter how big your aperture or observatory.

but you took all that as vaguely insulting, and i regret i helped you get there.


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Dennis_S253
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Re: unlearning the constellations new [Re: drollere]
      #5479133 - 10/19/12 04:58 PM

I knew I should stay away from this. Starting with the title, "unlearning the constellations". They have been around for thousands of years. They are guides. We say things like, look for M42 in Orion by the sword. That's an area where new stars are forming. I'm not sure what big picture you want I guess. Yes the galaxy is huge. The universe is a lot bigger. Yes, I guess you could say we are looking through pinholes. I can't see it without the pinhole though. There are a lot of good TV shows that talk about the big picture. History channel, discovery and a few more. There are some good books, The universe as we know it. I'm sure there's a lot more.

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drollere
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Re: unlearning the constellations new [Re: Jon Isaacs]
      #5479146 - 10/19/12 05:07 PM

Quote:

We all enjoy the sky in a different way... I very much enjoy just wandering around and seeing what I can see, figuring out what it is, learning something about it... I don't use GOTO, I view the constellations as part of the road map, sign posts to help me find my way from one part of the sky to another.

I am a big believer in using a telescope as an instrument of discovery rather than as tool to go down a list of objects... For me, it's not the science as much as it is the aesthetics, I just enjoy looking through a telescope/binoculars/naked eye at the night sky... It's just neat being out there under the night sky.



there is a whole physical, sensual, spiritual, emotional and esthetic dimension to astronomy, certainly. it is neat, but i wasn't addressing it specifically.

there are many ways to see, study, appreciate, enjoy the night sky with the use of optical instruments. whatever anyone wants to do, however they want to do it, is fine with me. (as if what i thought had the slightest importance to how or why they want to do what they do.)

i *am* saying that there are walls around the common approach. once you look for them, they are palpable. the novice asks, "what is the best magnification?" -- the advice is: why, the magnification that frames the object. start with the object, which can't be more than a few arcminutes wide, and put a frame around it. cut out everything else, ignore it, assume it doesn't matter. then go on to the next object, put a frame around that, and so on.

what's a good book about astronomy? well there's this book here, that gives you a *list* of things to look at, or a chapter on each of 100 objects, all separately described. ... and how many other books are just like that one? isn't there fundamentally a routine and limitation in the *information resources* available to us? aren't we habituated to look at the sky in a certain way by how we find things to look at?

the point made above about light pollution is right on. glare does nudge us to look for bright, discrete, identifiable targets, because the milky way is blotted from view. but so too do books and atlases that never indicate there is anything else to see, that show the milky way as a smear of monotone. it's remarkable that one of the most intimate and detailed descriptions of the whole milky way available anywhere is in ... ptolemy's almagest, Book VIII.

i greatly admire jon's approach to observing, and i endorse it as incredibly pleasurable. i once started from beta cygni and worked my way by random slews up through gamma and out to delta, and still remember it as something like a boat cruise up an enchanted river. i discovered many things that i could not later identify with a catalog. i was the tourist who just puts the tour guide in the backpack and wanders up an alley.

but also like the tourist who wanders without a map. it's not just that we habitually look in a certain way, and there is another way to look: it's that we don't have the resources to make any other way of looking informative. fun and stimulating, yes, but enriching, insightful, illuminating, educational? if we had signposts as we wandered, the whole experience would be more memorable. we could actually see and comprehend our place in the galaxy.

i liked the suggestion made about a software program focused on these topics. where can i get it? the software > Where is M13? < is a rudimentary version of what i had in mind, but it does not link the objects to the visible milky way, but to a galaxy schematic.


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bumm
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Re: unlearning the constellations new [Re: drollere]
      #5479416 - 10/19/12 08:10 PM

As one who loves the constellations, I've sort of steered clear of this thread too... As near as I can tell, the suggestion here is that we should be viewing and understanding the universe as a whole, and not just objects as found on an artificially constructed map of the sky. That's fine... but I think most all of us with any curiosity proceed to assemble the pieces and gain an understanding of the universe as we enjoy observing it's fragments. While I'm sure you aren't suggesting that the constellations should be left behind as an obsolete artifact of times past, they also are a part of the big picture. While they are only chance patterns of moving stars seen from our particular location and time, they're a part of human history and experience, from the eighteen thousand year old picture of the Pleiades on the cave wall at Lascaux, to the most recent computerized star charts. Most every night, I go out and name all the stars I can, just so I never forget...
Marty


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Tony Flanders
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Re: unlearning the constellations new [Re: Dennis_S253]
      #5479431 - 10/19/12 08:16 PM

Quote:

I knew I should stay away from this. Starting with the title, "unlearning the constellations".




The title is probably unnecessarily combative. I think "Beyond the Constellations" would be more accurate.

For me, the greatest glory of astronomy is that there are so many different ways to approach it. There had better be! It is, after all, the study of the universe -- literally, everything that is, has been, or ever will be. I find the aesthetic approach, the historical approach, the study of individual objects and stars, and the study of how they fit together, all equally interesting.


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FirstSight
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Re: unlearning the constellations new [Re: Tony Flanders]
      #5479475 - 10/19/12 08:47 PM

For those among us who usually have to put up with mag 5 or lesser skies, a trip to a true mag 7+ gray or black site on a moonless night, especially when the summer Milky Way is ascendant, IS of itself a FORCED lesson in "unlearning" the constellations. It can take awhile before you begin to recognize familiar constellation landmarks because they're lost amid the unfamiliarly dense swarm of visible stars and steamy knots of the indistinct glow of millions of stars too faint to see individually, and the winding dark nebular rivers running in-between the clouds of stars.

Edited by FirstSight (10/19/12 08:52 PM)


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auriga
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Re: unlearning the constellations new [Re: drollere]
      #5479536 - 10/19/12 09:34 PM

Bruce,
A number of points:

1. Your gifs are great and show a lot about the sky that other representations don't show. I agree with you that these alternative representations of the sky are valuable. Thanks for posting them.

2. You raise very important questions. As far as I can tell, the Herschel 400 I and II, while no doubt valuable and worthwhile, convey little understanding of the structure of our galaxy as a whole. Observing lists in general can have this limitation. So I agree with this part of your thesis as well.

3. The pinhole view is narrow in the sense that one is observing only a small portion of our galaxy. But with my 13 Ethos ( I don't have the 17) in my 16"f/4 Dob the view is perceptually wide, 100 degrees wide. Al Nagler is right about the "grandeur factor." The emotional and perceptual sense of the breadth and vastness of our universe is conveyed in part by these huge visual fields even though in terms of absolute distances they are very narrow indeed.

4. There are some guides in the area of galactic structure. Prime among them, and going far beyond Craig Crossen's Binocular Astronomy, is his subsequent book, with Gerald Rhemann, "Sky Vistas" (published by Springer). He devotes great attention to the structure of our galaxy. Another guide is Bill Tschumy's "Where is M13?" I am sure you are familiar with these but my point is that a huge amount can be learned about the structure and content of our galaxy by careful study of these sources, which you have doubtless already done.

6. If your thesis is that we need to spent time scanning the Milky Way with binoculars, looking for star clouds, dust lanes, dark nebulae, and OB associations, in order to get an understanding of and appreciation for our own beautiful galaxy, I agree entirely.

7. Where I part company with your thesis is as follows: When I look at M17 I enjoy it as an object in itself, but I try also to be aware of where it lies in our galaxy. I value diagrams like "Where is M13" that show it visually. And I devote special attention to objects that are far out toward the Perseus arm, such as the Double Cluster and one or two more distant objects in that direction. I also try to look at objects near the galactic center, such as NGC 6522 and 6528, in Baade's Window, with the realization of where they are; similarly for objects in our Orion Arm. My point here is that viewing individual objects is not exclusive of understanding the galactic structure, and that binocular study, while essential for this purpose, is not the only contributor to this understanding.

Knowing where in our galaxy an object is, adds a great deal to the pleasure of observing it and to my understanding of the object and our galaxy. To know that M54, while not outstanding visually, is probably the core of a now dispersed galaxy, enriches the visual experience.

I am also very interested in viewing the sky in terms of the absolute brightness of the stars in it. So, I always like to take a look at Zeta 2 in Scorpius, and 6231 is itself one of my favorite objects. And Rho in Cassiopeia, and P Cygni, and Wesen and Aludra in Canis Major.

As a related issue, I think the OB associations, especially in Perseus and Scorpius, are much neglected by observers. Perhaps because they are too easy to find and so don't confer much prestige on the observer?

Bill Meyers


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Re: unlearning the constellations new [Re: drollere]
      #5479684 - 10/19/12 11:11 PM

Quote:

[...]a large part of that has to do with the pinhole mentality[...]

[...]put that 17mm 100 $800 tele vue ethos in your 16" /4 dob[...]

[...]we piece together glimses of these pinhole samples of the sky as isolated features with nonsense pidgin arabic or cartoon character names, and call it "astronomy" with the absurdity of someone who has a pet name for every piece in a 100 or 1000 piece jigsaw puzzle but has never put the puzzle together to see what it represents.[...]

[...]constellations only cement the delusion[...]

[...]the problem seems so big that it's hard to know where or how to begin.[...]

[...]perhaps we look at far away objects in isolated and tiny fields of view because ... it is just so much easier to do.




Quote:

there are two ways to misinterpret a post, and you've done both.





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Man in a Tub
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Re: unlearning the constellations new [Re: drollere]
      #5479731 - 10/19/12 11:45 PM

Quote:

i liked the suggestion made about a software program focused on these topics. where can i get it? the software > Where is M13? < is a rudimentary version of what i had in mind, but it does not link the objects to the visible milky way, but to a galaxy schematic.




Try this:

http://www.haydenplanetarium.org/universe/about

It's free. I've had just about every updated version since I learned of it while reading Natural History magazine.


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Re: unlearning the constellations new [Re: derangedhermit]
      #5479773 - 10/20/12 12:29 AM

The unfortunate use of one word--"unlearning"--seems to have diverted some readers from the true spirit of Bruce's thesis. As Tony has suggested, a title more along the lines of "Beyond the Constellations" would have more accurately conveyed Bruce's intentions.

As I read it, and practice myself, the 'pinhole' view is not unappreciated, and certainly not denigrated. Indeed, it's vitally necessary in order to discern any kind of detail for the smaller and more distant objects. The point is that most backyard observers tend to focus overly much on an object in isolation, where a broader perspective would engender even greater appreciation.

The kind of study required to build a fuller picture need not occur in the field, where precious eyepiece time can be more fruitfully allocated to the detailed picture. We now have many resources at our disposal:
- Books, such as Crossen's Binocular Astronomy, Crossen and Reihman's [sic] Sky Vistas, Couper and Henbest's Guide to the Galaxy, to name a few.
- Software, like Hayden Planetarium's Partiview (highly recommended!). [in Edit: Todd beat me to it]
- Atlases, like The Cambridge Photographic Sky Atlas.
- Online images, milky way mosaics (especially), etc.

Cloudy nights (yes ) can be put to good use doing the 'deskwork'.

In my own case, I learned the 2-D geography of the sky very rapidly in the early- to mid-eighties by taking tripod-mounted photos on high speed film, of no more than 60 seconds' duration, through 28mm and 50mm lenses. With prints in hand, I would annotate all the DSOs captured (and there were lots!) by comparing with the venerable Skalnate Pleso atlas.

My journey on the discovery of our home Galaxy began in earnest when I obtained the book, "Guide to the Galaxy" in 1992-3. It included plan view charts which mapped out the Galaxy as then known, with a good amount of detail in the Sagittarius, Cygnus-Orion and Perseus arms.

Soon afterward Binocular Astronomy further cemented some details.

The next big leap came with my discovery in 2003 of Partiview, a 3-D software package available as a free download. The interface is not exactly intuitive, being seemingly designed more for engineers. Indeed, Partiview is really a generic particle visualization tool, adapted for astronomers simply building suitable databases. Get through the tutorial and you'll at least be able to fly about through space and really get a feel for the arrangement of stars, clusters (open and globular), associations, nebulae (including planetaries), and even pulsars. I love this stuff!

And do I learn it just for me? Nope. At a star party I typically regale those waiting for a telescopic view with a story. In a couple or few minutes I might cover:
- The 475 l-y distant Upper Scorpius OB association, comprising the near-its-end supergiant Antares and other stars of the heart and claws.
- The runaway star zeta Oph, which departed Upper Sco 1 millin years ago after a SN explosion, and us currently lighting up a 10 degree wide, dim nebula as it traverses the Ser-Oph rift of dark clouds, among the nearest to us. The other remnant from the SN blast is a pulsar (neutron star), flying rather faster and so is located well away in Aquila.
- The great difference in the distance to dark clouds toward the central milky way: The Ser-Oph rift of dark clouds, as near as ~400 l-y, which diverge northward from the band of the milky way and extend well up into Ophiuchus; The ~5,000 l-y distant Great Rift lying along the galactic equator, which resides mainly along the outer edge of the Sagittarius spiral arm and inside of which the Lagoon nebula resides.
- The recession into the distance of the nearby Rift clouds which lie essentially along the inner edge of our own local spiral arm, starting at Ser-Oph at 400-500 l-y, terminating in Cygnus some 3,000 l-y away.
- The importance of these dark clouds, because they contain from thousands to millions of Sun's worth of molecular gas, from which future stars, solar systems and stargazers will be made.


And more besides, time and interest permitting.


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Astrodj
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Re: unlearning the constellations new [Re: Man in a Tub]
      #5479833 - 10/20/12 01:50 AM

"Try this:

http://www.haydenplanetarium.org/universe/about

It's free. I've had just about every updated version since I learned of it while reading Natural History magazine."


This is terrific! Looks like someone imagined it way before I did, and did something about it too!

Thanks.


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Man in a Tub
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Re: unlearning the constellations new [Re: Astrodj]
      #5479873 - 10/20/12 03:04 AM

Hope you like it as you learn the GUI. When you travel away from the solar system in the Milkway Atlas of Digital Universe, do turn off the constellation lines. Otherwise, your computer screen will look like an interstellar game of pick-up sticks.



Edited by Man in a Tub (10/20/12 04:02 AM)


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auriga
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Re: unlearning the constellations new [Re: GlennLeDrew]
      #5480351 - 10/20/12 12:58 PM

I have Cooper and Henbest. Lots of good information in a remarkably ugly book.
Bill Meyers


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Re: unlearning the constellations new [Re: auriga]
      #5480405 - 10/20/12 01:27 PM

here's another way to approach the issue.

here's a basic test: take the test, and see how you do. note that these are all "landscape" questions -- none have to do with astrophysics, cosmology, or any other arcane expertise. these are all questions of the type -- "you're in yosemite valley, where is half dome?"

if you don't do so well, then perhaps you should give my post a second thought?

1. A novice asks you, "Where is the center of our galaxy?" Where do you point, and how far away do you say it is?

2. A novice asks you, "As the Sun revolves around the center of the galaxy, in what direction is it headed?" Where in the sky (or at which star) do you point?

3. There are 20 "bright" stars (v.mag. > 2.5) within twenty parsecs of the sun -- our near companions in our galactic journey. Name five.

4. How many other stars, besides these 20 bright stars, are within 20 parsecs of the sun?

5. The sun is most closely associated with a specific spiral arm of the galaxy. Which one?

6. This spirial arm is visible as a large part of the Milky Way. From our viewpoint on Earth, where does this spiral arm appear to start, and where does it end?

7. What is the closest galactic star cluster to Earth?

8. Where is the closest region to Earth where stars are actively being formed?

9. The Milky Way appears to divide into two bands in what part of the Milky Way? What causes this separation?

10. What is the farthest part of the Milky Way that we can see from Earth? Where is it, and how far away is it?


i'll wait for some answers (or individual tallies of the number of questions that can be answered), before i post answers of my own.

edit: wording of two questions clarified.

Edited by drollere (10/20/12 03:55 PM)


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Re: unlearning the constellations new [Re: Tony Flanders]
      #5480529 - 10/20/12 02:48 PM

Quote:

The title is probably unnecessarily combative. I think "Beyond the Constellations" would be more accurate.

For me, the greatest glory of astronomy is that there are so many different ways to approach it. There had better be! It is, after all, the study of the universe -- literally, everything that is, has been, or ever will be. I find the aesthetic approach, the historical approach, the study of individual objects and stars, and the study of how they fit together, all equally interesting.



well, from my side, "beyond the constellations" has too specific a spatial or too vague a metaphorical thrust. it is also, as a rubric, hackneyed to the point of parody ("beyond the valley of the dolls").

the constellations are, after all, the anchor for a traditional way of talking about and observing the sky. "showcase doubles in cygnus," "deep sky objects in leo" -- these are just ways to dole out a ration of tiny objects in tiny corners of the sky, an approach that is encouraged by our books and the nature of our equipment. and perhaps by the fact that few of our peers point out that "hey! there's another way!"

and, since you mention it, i'm not saying we need to burn books that refer to ancient or striking asterisms. i'm saying they are fundamentally not an informative or insightful way to organize our "mental map" of the sky. the constellations were created to mark seasons, anchor myths, assert the superstitions of astrology, flatter patrons and fill unnamed territory in star atlases. we have more justification to divide the study of geology by state boundaries or to organize the periodic table with alchemy.

i have to say, purely as my own personal idiosyncracy of idiopathic solipsism and errancy, that i'm flabbergasted by the fact that, because i advocate what seems to me to be a fairly unpopular or unexplored way to think about astronomy, everyone has to affirm that there are many other ways to do astronomy and that they are all equally valid and fun and interesting.


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Re: unlearning the constellations new [Re: GlennLeDrew]
      #5480536 - 10/20/12 02:50 PM

Happy birthday, Glenn.

- Jim


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drollere
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Re: unlearning the constellations new [Re: drollere]
      #5480594 - 10/20/12 03:29 PM

brief thanks and comments to the substantive posts ...

bumm ... i agree completely that the curious will get where they are going. my regret is that there aren't more references able to assist the individually curious. as i said, wandering is fun, but a map really helps. and glenn's post suggests how much curiosity is necessary to boot up an understanding of the big picture.

firstsight ... yes, i think light pollution has a lot to do with it, as you say the experience of a truly dark sky is awe inspiringly unfamiliar. and the more i think about it, the more that seems to be a fundamental objection. dispiriting indeed, but maybe realistic, to realize how much modern infrastructure blocks our view of fundamental things.

auriga ... wow, well just to the point where we "diverge" -- actually i was suggesting that we could use specific stars or objects as markers to larger features, in the way you and glenn demonstrate. which features, which markers? i suggested "unlearning" the constellations as preliminary to freeing up individual stars for other purposes. do we really need the *constellation* scorpius in order to outline the OB association in that part of the sky?

... yes, the view through a 100 ethos is flattering and entertaining. so too is the marketing behind it. chasing messier objects and knocking down herschel or double star lists, all great and rewarding challenges (i've done it myself). articles that focus on constellations or cosmology -- entertaining, popular, widely used. but look how all those things point our attention and expectation in a specific direction. it amounts to an established culture.

glenn ... you're the man. i've noticed many others with similar preferences for big sky and wander watching, but you and jon are the most frequent and genial advocates.

todd ... thank you for the hayden planetarium pointer! i tried downloading the software in the past but it didn't work for me for some forgotten reason. i'll try it again.

bill ... the couper/henbest book looks very interesting -- i just ordered it, ugly or otherwise.


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auriga
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Re: unlearning the constellations new [Re: drollere]
      #5480605 - 10/20/12 03:39 PM

Quote:

here's another way to approach the issue.

it's a simple test: take the test,

[but not simple to give the correct answers. And may be contaminated by a correlation to verbal I.Q.]

and see how you do. note that these are all "landscape" questions -- none have to do with astrophysics, cosmology, or any other arcane expertise. these are all questions of the type -- "you're in yosemite valley, where is half dome?"

[Okay, I'll bite.]

if you don't do so well, then perhaps you should give my post a second thought.

[Even if we do well your post deserves careful thought.]

1. A novice asks you, "where is the center of our galaxy?" Where do you point, and how far away do you say it is?

[Unfortunately novices don't ask questions like these. If they do, say " "Hurry, you'll be late for your class at Cal Tech!"]

[Sagittarius, 30,000 ly.]

2. A novice asks you, "in what direction is our rotation around the center of the galaxy taking us?" Where (or at which star) do you point?

[Deneb and Gamma Cygni are rotating away from us].

3. There are 20 bright stars (v.mag. > 2.5) within twenty parsecs of the sun -- our near companions in our galactic journey. Name five.

[Alpha Centauri, Vega, Arcturus, 61 Cygni, Sirius.]

4. How many other stars, besides these 20 bright stars, are within 20 parsecs of the sun?

[Hundreds So-called "red dwarfs," and "brown dwarfs," not readily visible because of dimness.]

5. The sun is most closely associated with a specific spiral arm of the galaxy. Which one?

[Orion arm.]

6. This spirial arm is visible as a large part of the Milky Way. From our viewpoint on Earth, where does this spiral arm appear to start, and where does it end?

[Sagittarius to Cygnus. May actually start in Ara or Centaurus or somewhere down there.]

7. What is the closest galactic star cluster to Earth?

[Big dipper. Followed by the Hyades.]

8. Where is the closest region to Earth where stars are actively being formed?

[Orion nebula.]

9. The Milky Way appears to divide into two bands in what part of the Milky Way? What causes this separation?

[Cygnus. Dark clouds of interstellar dust.]

10. What is the farthest part of the Milky Way that we can see from Earth? Where is it, and how far away is it?

[Perseus arm, about 20,000 light years. I believe we can't see objects in the External Arm beyond the Perseus Arm, with most amateur telescopes.]

i'll wait for some answers (or individual tallies of the number of questions that can be answered), before i post answers of my own.

[We may learn something from our wrong answers.]

Bill

Edited by auriga (10/21/12 12:00 PM)

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mwedel
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Re: unlearning the constellations new [Re: drollere]
      #5480635 - 10/20/12 03:59 PM

Quote:

indeed, despite your claim to have equal and diverse interests, i note that you prefer to critique rather than build on my post.




There's one more way to misinterpret a post, and you've managed it. I don't think anyone in this thread objects to the factual information you're presenting, but to your adversarial tone. So let's stop slinging mud at each other's posts and get back to the question at hand.

Appreciating the distribution of nearby stars and the 3D structure of the Milky Way is not the only way in which we need to escape what I call the tyranny of spherical astronomy. There is also the 3D structure of the larger universe: the distribution of galaxies in the Local Group, the distribution of other clusters of galaxies, near and far, and the organization of these clusters into superclusters and other large-scale structures.

My appreciation of this perspective started when I realized that as essentially stellar objects, the planetary nebulae easily visible in amateur telescopes are mostly distributed within a few hundred light years of the sun. Open clusters go out to a few thousand light years, globs are mostly at tens of thousands of light years to hundreds of thousands of light years, although only a few of those more distant ones are visible in small telescopes because of the sun's position in the galaxy. And so on out to the Local Group galaxies at a few million light years, the Virgo Cluster galaxies at tens of millions of light years, and more distant galaxy clusters at hundreds of millions of light years.

To me, one of the most interesting aspects of this is that all of the classes of objects listed above include at least a few members that are close enough in apparent magnitude, as seen from Earth, to potentially be mistake for each other--or for comets, which is how Messier got into this in the first place (and yes, I know that later on he was trying to catalogue all kinds of DSOs, not just those easily mistaken for comets).

I realize that I've neglected OB associations, dark nebulae, and other large-scale galactic features. It's because I'm coming to this as a DSO list-chaser, and it's just easier to find information on the Messier-type objects. But I'm trying to hack my way in the right direction, even though I still have a long way to go.

Anyway, starting with double stars and planetary nebulae and moving out to the other classes of objects, one can bring larger and larger spheres of space into some kind of three-dimensional understanding, if the distances to the objects are known, and also if there is some kind of framework, mental or otherwise, to hang them on. I wish I had a manually interactive 3D holographic map of the kind seen in movies (Iron Man, Prometheus, etc.). Two-dimensional representations that attempt to show the 3D galactic (and extragalactic) structure are better than nothing, but they always compress one dimension out of existence,even if it's represented as 'perspective', and I still have to do the final 3D reconstruction in my head.

Still, it's a start.


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auriga
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Re: unlearning the constellations new [Re: GlennLeDrew]
      #5480691 - 10/20/12 04:52 PM


It is good to have someone sensitive enough to language to be interested in the title of the thread, though I see it a bit differently from you.

To me it's a metaphor, and as such a recognized literary device to gain the reader's attention and make the issues more salient. Perfectly okay with me, evidently not with others, who find it adversarial or provocative.

"Beyond the constellations" is to my ear quite ambiguous, and may refer to distant galaxies, or to substituting astrophysics of star formation, for conventional star lore.

The title the OP chose instead expresses the author's intent to conceive of star patterns in terms of absolute magnitude, or in terms of distance, or position in the galaxy. His gifs express this also.

I think there is a more general issue here about which constitutes really good writing in amateur astronomy. Thankfully, some writers are able to avoid the wooden, the clumsy, and the pedestrian. Among the really good writers are Craig Crossen, Jay Freeman, Rod Mollise, Robert Burnham Jr., William Tyler Olcott, James Mullaney, Charles Wood, and some others. From his posts here, Jon Isaacs appears to me to be a very good writer.

But some of our most brilliant posters do have difficulty expressing themselves clearly, as some of the posts on collimation suggest to me. And a lot of the books on amateur astronomy, even some very useful and well-regarded ones, are undistinguished in writing style. This is okay, I greatly appreciate the information and the expertise, but I am always happy to see good writing accompanying it. The OP here has a lively style, provocative perhaps but not boring.

Bill

Edited by auriga (10/21/12 02:17 AM)


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amicus sidera
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Re: unlearning the constellations new [Re: drollere]
      #5480805 - 10/20/12 06:30 PM

Many thanks for the thoughtful and very relevant OP, Drollere.

It's true that the vast majority of observers perceive and learn the stars as being fixed equidistantly on a 2-D shell above us... due to the lack of stereo effect due to distance, this is to be expected, and is still a good first step in becoming acqainted. If I may be so bold as to interpret what you have stated, I gather you feel that many stop at this point, and thus limit themselves as to their perception of the visible Universe, which tends to inhibit growth as an observer. If so, I am in agreement with you.

Your use of the term "unlearning" appears to be quite accurate in the context in which you have presented it. I fail to see how its use could be construed as either combative or unfortunate; these are emotive terms that would seem to be misapplied in this case.

That said, instead of completely discarding and hence "unlearning" the system in common use, perhaps a parallel system or systems could coexist alongside it... taking such denominators as distance, spectra and galactic distribution into account, either together or separately. This could effectively create a system that would include the diversity of distances, composition, distribution, etc., and hence provide a much deeper view of our surrounding stellar environment.

The animated maps you have supplied (very nice work, incidentally) are a step in this direction. Perhaps a whole-sky map of this sort, while still limited to a 2-D representation, would, with sufficient applied mentation, certainly expand the viewpoint of the average observer to include much more in his cognition than the "pinhole mentality of the catalog list and GOTO mount" that you refer to.

One book that might prove to be of interest in pursuit of the foregoing is the modest atlas entitled 3-D Star Maps, by Monkhouse and Cox (Harper & Row, 1989)... while quite basic, it nicely illustrates the concepts under discussion, and includes "depth" charts of not only our own stellar neighborhood, but of local galaxy clusters as well. It comes supplied with a pair of the requisite glasses to enable use of the 3-D maps.

eta: Is it just me, or has anyone else noticed that forumites are getting a wee bit touchy over trifles these days?

Edited by amicus sidera (10/20/12 07:04 PM)


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Re: unlearning the constellations new [Re: auriga]
      #5480830 - 10/20/12 06:53 PM

Quote:

Bruce,
A number of points:

1. Your gifs are great and show a lot about the sky that other representations don't show. I agree with you that these alternative representations of the sky are valuable. Thanks for posting them.

2. You raise very important questions. As far as I can tell, the Herschel 400 I and II, while no doubt valuable and worthwhile, convey little understanding of the structure of our galaxy as a whole. Observing lists in general can have this limitation. So I agree with this part of your thesis as well.

3. The pinhole view is narrow in the sense that one is observing only a small portion of our galaxy. But with my 13 Ethos ( I don't have the 17) in my 16"f/4 Dob the view is perceptually wide, 100 degrees wide. Al Nagler is right about the "grandeur factor." The emotional and perceptual sense of the breadth and vastness of our universe is conveyed in part by these huge visual fields even though in terms of absolute distances they are very narrow indeed.

4. There are some guides in the area of galactic structure. Prime among them, and going far beyond Craig Crossen's Binocular Astronomy, is his subsequent book, with Gerald Rhemann, "Sky Vistas" (published by Springer). He devotes great attention to the structure of our galaxy. Another guide is Bill Tschumy's "Where is M13?" I am sure you are familiar with these but my point is that a huge amount can be learned about the structure and content of our galaxy by careful study of these sources, which you have doubtless already done.

6. If your thesis is that we need to spent time scanning the Milky Way with binoculars, looking for star clouds, dust lanes, dark nebulae, and OB associations, in order to get an understanding of and appreciation for our own beautiful galaxy, I agree entirely.

7. Where I part company with your thesis is as follows: When I look at M17 I enjoy it as an object in itself, but I try also to be aware of where it lies in our galaxy. I value diagrams like "Where is M13" that show it visually. And I devote special attention to objects that are far out toward the Perseus arm, such as the Double Cluster and one or two more distant objects in that direction. I also try to look at objects near the galactic center, such as NGC 6522 and 6528, in Baade's Window, with the realization of where they are; similarly for objects in our Orion Arm. My point here is that viewing individual objects is not exclusive of understanding the galactic structure, and that binocular study, while essential for this purpose, is not the only contributor to this understanding.

Knowing where in our galaxy an object is, adds a great deal to the pleasure of observing it and to my understanding of the object and our galaxy. To know that M54, while not outstanding visually, is probably the core of a now dispersed galaxy, enriches the visual experience.

I am also very interested in viewing the sky in terms of the absolute brightness of the stars in it. So, I always like to take a look at Zeta 2 in Scorpius, and 6231 is itself one of my favorite objects. And Rho in Cassiopeia, and P Cygni, and Wesen and Aludra in Canis Major.

As a related issue, I think the OB associations, especially in Perseus and Scorpius, are much neglected by observers. Perhaps because they are too easy to find and so don't confer much prestige on the observer?

Bill Meyers




I agree with number 5


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derangedhermit
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Re: unlearning the constellations new [Re: bassplayer142]
      #5481203 - 10/20/12 11:35 PM

Ref "Where is M13?": it looks interesting, but I do not allow Java to be installed on any PCs I support.

The OP has reiterated a belief in the need to "unlearn the constellations".

I find being specific to be very helpful in clarifying concepts, so:

If we are to discard the current system, it seems fair to ask what we shall use in its place. So, when we stand under the night sky and look up, what identification and navigation system do you propose we use in place of constellations and ancient star names or Greek letters?

Since the OP places Ptolemy's Milky Way description at the top, a great example of the advantages of the new naming and navigational system will be a rendition of the Almagest Book VIII Part II (the description of the Milky Way), and the relevant parts of Book VIII Part I, Ptolemy's listing of stars by constellation, on which that description is based. Can we agree on Toomer's translation, first Princeton Paperback edition (1998), H177-H180 (p.403-404)? Can you now give us a flavor of how that will read using the new system?

Another good test will be an all-sky map to compare and contrast against the ubiquitous Orion DeepMap 600 that corrects the thinking that created it. That will be very useful in understanding the proposal (if all-sky maps are to remain).

Is it so that the very popular S&T Pocket Sky Atlas must also be replaced ASAP?

And any additonal specifics, beyond answers to these questions, on the proposed way forward will be illuminating.


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Re: unlearning the constellations new [Re: Astrodj]
      #5481403 - 10/21/12 04:11 AM

Quote:



I think people who have been at this a while are aware that distance variations exist between stars of the constellation asterisms, star brightness is apparent not absolute, and that the groupings are line of sight. It is probably the rare individual that can look at a given constellation and recall from memory the different distances of even the brightest members, forming a mental 3D image. Sounds like maybe a good place to start actually.




My books have been mentioned by a couple contributors to this discussion as good resources for getting a 3-D perpective on the night sky. And in fact the approach you describe here is exactly how I did start in the winter of 1979 in developing what I came to call "Galactic depth perspective." I had decided to study the sky constellation-by-constellaton with 10x50 binocs, Burnham's Celestial Handbook, and the Skalnate Pleso Atlas of the Heavens. I began with Orion and Canis Major, making data lists from Burnham's discussions of individual bright stars and important objects. Then I realized that I could not really absorb the information in these data lists unless I actually memorized them--specifically, the location of the Greek-lettered stars in the constellation, and the magnitudes, distances, and spectral types of the brightest of these stars (Burnham discusses every star of at least mag 3.50). I would run through this data outside at night while actually looking at Orion and Canis Major and soon found myself thinking in terms of the stars' relative distances.

I was very fortunate with where I began (though it was a wretchedly cold Minnesota winter that year) because Orion and Canis Major are good places to start in seeing the night sky in three dimensions. Most of the bright stars in Orion are part of the Orion Association, except for Betelgeuse and Belletrix, which are in the foreground of the Association. And most of the bright stars in southern Canis Major are members of the CMa Association, except for the foreground Epsilon. And Sirius is so much in the foreground of the CMa Association that, by comparison, it seems to be barely beyond the Moon!

And you can easily take the relationship of Orion to Canis Major to the next level of Galactic depth perspective: The CMa Association is both farther from us than the Orion Association and farther "behind" us in that it is roughly toward the direction from which we have come in our orbit around the Center of the Galaxy (galactic longitude 270 in Vela). Thus Orion and Canis Major trace a segment of a spiral arm of our Galaxy. And so by the end of January 1979 I found myself, much to my surprise, already tracing the local spiral structure of the Milky Way.

Much the same approach can be used on the opposite side of the Milky Way, where most of the bright stars from Scorpius on the northeast to Crux on the southwest are part of the much-elongated Scorpio-Centaurus Association. Anybody who has learned the constellations in that 80 length of the Milky Way will have no difficulty at all in envisioning the Sco-Cen Association, nor even in seeing that association's subgroups.

Thus I have found the constellations, old and largely artificial though they be, as useful guides into Galactic astronomy. But I think they are worth learning not merely for their utilitarian value. Most of the 49 constellations we inherited from Graeco-Roman astronomy actually go back to ancient Mesopotamian, and some of these can be reliabily dated (on art-historical and archaeological grounds) to the 5th millennium BC. Thus the constellations preserve the whole history of Western civilization, from its origins in southern Mesopotamia in the 5th millennium BC to European Enlightenment, when Lacaille burdened the sky with small star patterns carrying big names. Would you tear down some of the famous 19th century observatories simply because they have been rendered useless by urban sprawl and its resultant light pollution? I don't think so! The constellations should be thought of in the same way: as part of the heritage of the science we all so much love.

Craig Crossen


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bumm
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Re: unlearning the constellations new [Re: Crossen]
      #5481707 - 10/21/12 10:39 AM

For what it's worth, some aspects of this thread reminded me of a short chunk of a longer thing I once posted in sci.astro.amateur... I googled it up, and it was in May of 2005.

I looked at the horizon. The Milky Way was probably lying right along it, but I knew I wouldn't see it tonight, especially with that moon... I thought about how the dim Winter Milky Way must be along the horizon behind me. I was sitting upright in the galaxy, swinging in my chair,
heading in the general direction of Vega.
Marty


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Re: unlearning the constellations new [Re: Crossen]
      #5481725 - 10/21/12 10:57 AM

A resource that don't recall being mentioned yet is Celestia. Writing code for it, if you are not used to that kind of thing, has a steep learning curve. But there are user-friendly functions that can effectively allow the user to "zoom" in on any part of the sky to see where various objects are in relation to others. Unfortunately, it doesn't provide the distances or other information to the stars. But it is free, an certainly useful if one wishes to "see" the universe with more of a depth-perspective applied to it.

(To get an idea of how it looks, I used it to create some 3-D "zooms" of the Hyades, Pleiades, and Orion's belt stars in a few of my weekly astronomy videos.)


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Re: unlearning the constellations new [Re: bassplayer142]
      #5481987 - 10/21/12 01:52 PM

bassplayer, you gave me my first in a *vurrry* long time outright laugh on CN.

the fact that you noticed ... the fact that you were motivated to post by the notice ... the fact that you managed to find the most succinct riposte ... or maybe it's my morning brandy coffee.

anyway ... i owe you one.


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Re: unlearning the constellations new [Re: drollere]
      #5482045 - 10/21/12 02:28 PM

auriga stepped up to answer the questions i posted, which will stand for all those who answered on their own.

i have to say that i couldn't answer the questions myself without referring to a reference work -- something i don't have to do to name messier objects, or famous double stars, or distances to galaxy clusters ... which is one aspect of the issue i am raising.

as for auriga's "score"... (2) the sun is headed toward a point south preceding vega, but cygnus is close enough; (3) the nearest "bright" stars are Alpha Centauri AB, Sirius, Procyon, Altair, Fomalhaut, Vega, Pollux, Denebola, Arcturus, Capella, Rasalhague, Alderamin, Castor AB, Caph, theta Centauri, Aldebaran, epsilon Scorpii, Hamal; (4) hipparcos catalogued about 1900 stars within 20 parsecs of the sun, though as auriga says there are many more that we can't see; (7) hyades and beehive are the closest galactic clusters, the "big dipper" is an association (it has no tidal radius, just a common trajectory).

actually, the "orion arm" or spur extends from somewhere in central cygnus all the way past orion and canis major. we are "behind" and somewhat inside this feature in relation to the galactic rotation. the orion nebula is three times farther than the ophiuchus and auriga-taurus star forming regions ... although these are mostly invisible to astronomers using visual scopes. i think orion is the closest one we can easily see.

the last question was a trick question, because i don't know the answer! i'd agree that it's probably in the "backward" direction of the perseus arm; crossan calls out the farthest visible galactic star cluster in that direction. but possibly something in the direction of the galactic nucleus.

in any case, aren't these, taken at face, pretty basic questions? the fact that any of us, as astronomers, would have to look them up is the issue i am pointing to.

speaking of ... crossan's "binocular astronomy" has been mentioned before, but i'll add my strong recommendation. it's a much better balance of history and modern astronomy, and is far more informative about the "big picture", than one finds in burnham jr. ... whom crossan much admires. it has some nice charts (for example, of the SCO-CEN association), but i regret that it doesn't have a little more specific representation of the local bubble and our views in different directions. to a large extent, it still adopts the "flat on the celestial sphere" representation of our galactic viewpoint.

this isn't really crossan's oversight. the spiral arms were not mapped in any detail until the 1970's, and only very recent research has begun to clarify the contours of the gould belt and local bubble -- for example:

http://www.aanda.org/htbin/resolve?bibcode=2003A%26A...411..447LPDF

i think we've accumulated enough research to paint a basic picture. my puzzle is, how? -- which visual features effectively mark the major landscape elements? what *are* the major landscape elements? should we just define them piecemeal, anatomically, or holistically and as examples of galactic dynamics? glenn called out the SCO-CEN association.

i was out last night deploring the feeble milky way appearance at my location. exploring the galactic structure, as has been said, is a dark sky activity, and perhaps more than any other visual pursuit this crystallizes what we lose with light pollution. something like flooding the grand canyon, so we have the electricity for more televisions.


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drollere
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Re: unlearning the constellations new [Re: derangedhermit]
      #5482117 - 10/21/12 03:19 PM

Quote:

If we are to discard the current system, it seems fair to ask what we shall use in its place. So, when we stand under the night sky and look up, what identification and navigation system do you propose we use in place of constellations and ancient star names or Greek letters?




this is the point exactly. i expressed my "puzzle" as ... where to turn among current references as a point of departure and a source of reliable guidance? but the quote defines the bottom line: where is this going, what is the point?

the first topic is that we have a place in a larger structure, and we can see our place in that structure as the milky way. so we should be able to see the milky was as the panorama of a dynamic structure, as having parts in relation to each other and to a common movement, as having points of articulation, as having distances among the parts. a minor but necessary fact here is realization that galaxies are, to a great degree, *transparent* -- we see through the orion spur into the perseus arm, and through both of them to see distant galaxies.

this is to me the database problem: there are galactic clusters and H-II regions throughout the perseus arm or the CAR-SGT arm or the orion spur; these markers can be brought together to outline the direction and anchor remembrance of the distance of these large features. globular clusters can mark the extent of the galactic disk and the approximate distance of its axis. bright, characteristic population II stars can be identified as well.

the second topic is that every spiral galaxy we see is a process, a machine for making stars and star systems. what are the ingredients and steps in this process? this gets to glenn's approach of pointing out the dark clouds and the SCO-CEN OB association. add to that the orion nebula as the intermediate H-II step and to anchor the opposite side of the gould belt; and there should be t tauri stars, other OB associations in cygnus and perseus, some easily seen bok gobules or compact barnard objects, galactic clusters young and old, giant stars, planetary nebulae, and supernova remnants to connect the galactic process to individual star development, element formation and recycling.

the third topic after structure and process would be time: how long the sun takes to revolve the galaxy, how long the sun has existed, the galaxy has existed, how we know these things, etc. but also the local history of our "momentary" place in the local bubble, how it fortuitously gives us long views in critical directions, what might have created it. (there is even a paper that correlates gould belt events with extinction events on earth, via the mechanism of nearby supernovae sending oort belt objects into collision with earth.)

finally, to return to crossan's celebration of antiquity and its lore, i'd think that was a topic i have addressed enough by now. anyone who wants to recount babylonian myths is welcome to it, and nothing said here will deter them. but the stars are empty of social and historical content. there is no reason to wed them eternally to any interpretation. to the extent a new interpretation is looked for, and new features are to be described, then astronomical objects are ready to stand to any purpose.

if humans once indulged the primitive vanity to use the stars to illustrate fictions and myths, then there is no reason humans cannot also adapt them to delineate scientific insights in a way that can better capture the interest of amateur astronomers and our insightful enjoyment of the night sky. there's a time to remember traditions, yes: the problem in this topic seems to be in knowing when to let go.


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The Ardent
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Re: unlearning the constellations new [Re: drollere]
      #5482156 - 10/21/12 03:45 PM

Bruce

I understand your viewpoint and motivations a little bit, being that you are challenging folks to see things a little differently, a little "out of the box"
The problem with unlearning the constellations is that so few astronomers really "know" the constellations. What does "knowing" the constellations really mean anyway?
One of my projects in my quest to "learn" the sky and constellations is to observe all the Flamsteed and Bayer stars of each constellation (where applicable) Why are there some stars in a constellation brighter than the Flamsteeds and Bayers that dont have either designation?

Another excecise is examining the border areas of the constellations and trying to mentally distinguish which stars are in each, when they are so close in the sky. I know the IAU borders arent scientific, but its a fun excerise.

Why dont the stars in Vulpecula look like anything at all?

A problem I have with associations is the lack of reference materials available to the amateur. I can look up individual stars in Skytools, and there may be a note that "this star is a member of the Cepheus OB1" but there are no charts with the associations plotted and member stars listed. I want to be able to observe 10-20 stars of each association and compare them with the field. Other than Sky Catalog 2000 Vol 2 (and thats brief) I havent found anything.

Regards


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auriga
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Re: unlearning the constellations new [Re: bassplayer142]
      #5482168 - 10/21/12 03:53 PM

I thought it was obvious: No. 5 can be found by interpolation. (Excel has a program for this.)

For those uninclined to interpolate,

5. As Crossen points out in Sky Vistas, small rich field telescopes can be used as a supplement to binoculars for exploring galactic structure. I have found the Starblast helpful in this regard.

Bill Meyers


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Crossen
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Re: unlearning the constellations new [Re: drollere]
      #5482177 - 10/21/12 03:57 PM

Quote:


crossan's "binocular astronomy" has been mentioned before, but i'll add my strong recommendation. it's a much better balance of history and modern astronomy, and is far more informative about the "big picture", than one finds in burnham jr. ... whom crossan much admires. it has some nice charts (for example, of the SCO-CEN association), but i regret that it doesn't have a little more specific representation of the local bubble and our views in different directions. to a large extent, it still adopts the "flat on the celestial sphere" representation of our galactic viewpoint.

this isn't really crossan's oversight. the spiral arms were not mapped in any detail until the 1970's, and only very recent research has begun to clarify the contours of the gould belt and local bubble




Thank you for the kind words about Binocular Astronomy. You are right about its chapter on the Milky Way: some things in it (though far from everything) are out of date, and I did not cover the far southern Milky Way. (I am of course speaking about the original 1st edition of Binoc Astro: I had nothing to do with the so-called 2nd edition, have not seen it, and therefore cannot say anything about its Milky Way chapter.) That chapter was based upon a 2-part article I published in the July and November 1983 issues of "Astronomy" magazine. However, the Galactic structure material in "Sky Vistas" is up to date. Moreover, it seems quite likely that next year a revision of my 1983 Milky Way article is going to be published and that article will not only have state-of-the-art information on the Milky Way's spiral structure, but cover the far southern Milky Way as well.

Craig Crossen


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Astrodj
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Re: unlearning the constellations new [Re: drollere]
      #5482494 - 10/21/12 06:45 PM

Quote:

the orion nebula is three times farther than the ophiuchus and auriga-taurus star forming regions ... although these are mostly invisible to astronomers using visual scopes. i think orion is the closest one we can easily see.




Just as a point of information...though also mostly invisible visually (especially from Missouri,USA)...

BHR 71, a Bok globule associated with the "Coalsack" (I am intentionally avoiding the use of constellation names to facillitate defining a locale in the galaxy, in the spirit of the thread), and listed in the catalog of southern Bok globules by Bourke, Hyland, & Robinson (1995), is also another nearby star forming region at 150 pc.

Now, would that be located relatively nearby in the Orion arm with us, looking in the direction of the Centaurus Arm?

<edit corrected "closest" to "also another nearby">

Edited by Astrodj (10/21/12 06:53 PM)


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derangedhermit
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Re: unlearning the constellations new [Re: Crossen]
      #5482695 - 10/21/12 09:15 PM

Quote:

My books have been mentioned by a couple contributors to this discussion as good resources for getting a 3-D perpective on the night sky.

Craig Crossen



Is "Sky Vistas" out of print? I can't find it for less than $80. Thanks!


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Re: unlearning the constellations new [Re: derangedhermit]
      #5482820 - 10/21/12 10:47 PM

Astrodj,
In answer to your last question, yes. At 150pc, it would lie in or near the edge of the Sco-Cen OB association (and is quite likely associated, too), which in turn lies more or less on the inner edge of the Orion-Cygnus arm.


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Astrodj
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Re: unlearning the constellations new [Re: GlennLeDrew]
      #5482968 - 10/22/12 01:03 AM

Glenn,

Okay, I think I see that. Then, if I am understanding correctly, the a fore-mentioned Auriga-Taurus star forming region would be in nearly the opposite direction, about the same distance?

And incidentally, does the Orion arm originate out of (like a spur) the Cygnus arm, with us being fairly near where the two arms diverge, say 1000-1500ly? Representations I can find of our galaxy's arms that name them are ambiguous.

It helps if I visualize our sun as the center of a sphere the size of the galaxy's thickness in our area, with radial spokes heading out in all directions and stopping at different distances. Mentally stretching that distance out(if required), if the direction happens to lie along the plane of the galaxy is easier for me to imagine that way.

Sorry for all the questions, I'm trying to build a better model in my head.


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Crossen
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Re: unlearning the constellations new [Re: derangedhermit]
      #5483065 - 10/22/12 03:51 AM

No, "Sky Vistas" is still very much in print. If you have found it for $80 I think you have done very well. It is an expensive book because its publisher, Springer-Verlag Vienna/New York, chose to print it on extremely high quality glossy paper so the numerous photos by master astrophotographer Gerald Rhemann could be seen at their best.

What is in fact out of print is "Binocular Astronomy" because, as I said, I had nothing to do with the so-called 2nd edition of that book. I've not seen a copy of this 2nd edition, but have been told that its text differs little from that of the original edition. This means that this "2nd edition" is VERY out of date since I wrote the original edition in the mid-1980s!

Craig Crossen


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Re: unlearning the constellations new [Re: Crossen]
      #5483353 - 10/22/12 10:21 AM

Astrodj,
Our Local arm, Cyg-Ori, is considered a 'minor' arm segment lying between the Sgr and Per arms. It originates at least 3,000 l-y away, in the direction of the Cygnus star cloud, and terminates at perhaps the same distance in Puppis. This is all kind of fuzzy, as I understand it. Spiral arm features are not generally sharply defined, with clear cut edges and termini. In the case of the Cyg-Ori arm, it could be more of a 'flocculent' feature elongated over periods of star formation (Gould's Belt being one such) by differential Galactic rotation, rather than a purely density wave feature.


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Astrodj
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Re: unlearning the constellations new [Re: GlennLeDrew]
      #5483707 - 10/22/12 01:49 PM

Glenn,

That helps, thank you.

To the OP, sorry if I strayed off topic. I probably should have PM'd.


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Re: unlearning the constellations new [Re: Astrodj]
      #5485243 - 10/23/12 01:01 PM

not at all, astrodj, your query illustrates the issue. you would have no problem at all answering some factual question about a messier object. or even what messier had for dinner the night he found it. or which mythical creature it is found in. or what babylonian clay retains a picture of it.

Quote:

I understand your viewpoint and motivations a little bit, being that you are challenging folks to see things a little differently, a little "out of the box"



hmmm ... my motivation is that astronomers can be aware at a basic level of where they are and what is around them in their own galaxy. my gif animations, linked in the original post, illustrate that the traditional constellations fail as signposts to the nearest bright stars and to galactic structure.

my other point was that we are "locked in" to the traditional constellations because of the huge library of reference resources that are organized around them. constellations can be useful as basic asterisms to learn one's way around the sky, and as arbitrary patches of celestial real estate. other than that, they are relics.

the fact that we see a dipper (rather than a bear or a plough) or a letter W (instead of a throne) or a teapot (instead of a centaur) in a specific asterism means that the traditional constellations can easily be reinterpreted for other ends. we are free to shape the sky to other didactic purposes, if useful.

rather than a cross, or a swan, cygnus could just as easily be repurposed and taught as a big "X" in the sky that marks the insertion of the orion spur into the sagittarius-carina arm (a very turbulent marriage, btw, one of the richest X ray regions in the galaxy), or vega repurposed as the general direction in which we are headed in the galactic revolution, or the front "T" of scorpius (omitting red antares from the bright white stars) as the heart of the upper scorpius OB association, or the cluster of stars around alpha persei as the core of the perseus OB3 association, or the teapot as pouring hot water on the center of the galaxy.

in the same way that cepheus, cassiopeia, andromeda and perseus all figure in the same mythological story, the progression from the orion nebula to T Tauri to the pleiades to the perseus OB3 to the hyades to the crab nebula can be taught as the natural progression of star creation -- they are all in the same part of the sky! some simple and very basic lore can be held in memory and explained to novices at no harm to anyone else's preferred mythology. those who want to speak of dragons and centaurs, bulls and birds can have at it.

Quote:

Why are there some stars in a constellation brighter than the Flamsteeds and Bayers that dont have either designation?



because in those days everything was done by candlelight. seriously ... flamsteed was an incredibly meticulous and repetitive astrometrician, but there are dozens of "lost" flamsteed stars that he recorded in locations where no star exists. instruments, records, comforts and scholarship were primitive in the 17th century, and mistakes happened.

Quote:

Why dont the stars in Vulpecula look like anything at all?



you can ask the same question about aries, cancer, virgo, pisces, capricorn, cepheus, leo minor, canis minor, lynx and aquarius! the level of "pretend" required here is perhaps why the "pretend" myths that go with the constellations become more digestible. but, to your point, vulpecula is a 17th century "scrap" constellation, invented to use up stars not already in a mythological figure.

Quote:

A problem I have with associations is the lack of reference materials available to the amateur. I can look up individual stars in Skytools, and there may be a note that "this star is a member of the Cepheus OB1" but there are no charts with the associations plotted and member stars listed. I want to be able to observe 10-20 stars of each association and compare them with the field. Other than Sky Catalog 2000 Vol 2 (and thats brief) I havent found anything.



if you are interested in the stars in or out of an association, a paper by DeZeeuw and colleagues, based on hipparcos data, is the basic reference. a more recent paper focuses on the SCO OB2 association specifically:

http://iopscience.iop.org/1538-3881/117/1/354/pdf/980283.web.pdf
http://arxiv.org/abs/0809.0407

incidentally, you would find both papers with the SAO/NASA archive query tool:

http://www.adsabs.harvard.edu/

look up any topic or keywords (author and year of publication is often enough) -- papers you can download as PDF files are coded "F" or "X". you can get really deep into the technical or mathematical weeds with many of the papers here, but you can also find some elegant and recent review or summary papers by a single author.

if you ignore everything but the charts, you'll find the de Zeeuw OB associations shown as individual stars. the problem with the de Zeeuw paper is that everything is shown in galactic coordinates. important to be familiar with and very useful to know immediately where something is in relation to the galactic landscape ... but not the familiar equatorial coordinates.

as a remedy, i use the Dame (2000) microwave map of the milky way as a foundation chart, then add data to it mashup style. for example, in THIS CHART i've added naked eye stars down to v.mag. 4, H-II regions, outlines of the approximate extent of local OB associations, and 50 parsec spheres drawn in perspective to illustrate relative distances. the chart has galactic coordinates marked, so objects in galactic coordinates can be located on the map. and visually it is instructive: the orion arm appears shredded and diffuse, because it is close to us, but the galaxy elsewhere appears dense and compact, because it is far away.

each of us is still on our own if we want to get beyond the constellation constriction. like the binary bias, it's just something you have to recognize on your own terms. if you decide it's worthwhile to look in a different direction, then there are people on CN happy to assist.

so ... my thanks to previous posts that pointed me to references i was unaware of. astronomy is fun because it is an opportunity for continuous learning.


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drollere
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Re: unlearning the constellations new [Re: derangedhermit]
      #5485295 - 10/23/12 01:30 PM

Quote:

Ref "Where is M13?": it looks interesting, but I do not allow Java to be installed on any PCs I support.



when i was coming up through the internet, java was going to be the esperanto of the digital age. now even apple won't support it.

Quote:

So, when we stand under the night sky and look up, what identification and navigation system do you propose we use in place of constellations and ancient star names or Greek letters? Since the OP places Ptolemy's Milky Way description at the top ... can you now give us a flavor of how that will read using the new system?



ptolemy represents a floor, not a standard. the point isn't that ptolemy is especially admirable ... it's that he at least saw the milky way as worth looking at, and that nobody since has looked at it with a comparable level of detail. (excepting things like the barnard survey photos ... one can find hundreds of lovely images, but a dearth of explanation of what we are looking at.)

Quote:

Is it so that the very popular S&T Pocket Sky Atlas must also be replaced ASAP?



no, just as it shouldn't be discarded because it does not show the traditional mythological figure overlays (as in every 18th century atlas).

i claim there is a general lack of single and compact resources to anchor the average amateur astronomer's understanding of our place in the galaxy, its broad structure and processes. if we throw out the traditional resources, we're left with nothing. i'd like to stimulate creation, not destruction ... for example, the animations created by "eyes on the sky" (kudos, dude!).


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Doc Willie
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Re: unlearning the constellations new [Re: drollere]
      #5485348 - 10/23/12 01:59 PM

If I understand what I recently read correctly, the next version of Sky Safari will have the capability of viewing the sky as seen from other stars. And I think you may be able to see the motion as to get there at warp speed. I wonder if any of the new planetarium projectors have that capability or if other PC programs such as Stellarium will be able to do it.

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Plan9
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Re: unlearning the constellations new [Re: drollere]
      #5485730 - 10/23/12 05:32 PM

Bruce,

I'm late to the party - just checked out the Observing forum and spotted your thread.

Your subject line and first post grabbed me - while I accept the usefulness of the constellations (at least it's a map and you can kind of find your way around the sky with it), they don't provide a framework for any deep knowledge. I'm keen to continue this discussion (maybe more future threads to keep from being unwieldy ?).

A couple of things I found in a few minutes of surfing that might be of use/interest (all wikipedia):

Local Bubble
Orion-Cygnus Arm
Perseus Arm

These talk about Milky Way structures that surround us; I wasn't actually familiar with these terms/structures.

Also, more software:
3D Galaxy Map

BTW, no need to be down on Java, esp for applications rather than applets - the Mac is the only platform I'm aware of that provides Java out of the box (and Apple just handed over support of it to Oracle - previously it had been rather neglected and behind the curve compared to the Windows version, which was always maintained by Sun then Oracle).

Quote:

i claim there is a general lack of single and compact resources to anchor the average amateur astronomer's understanding of our place in the galaxy, its broad structure and processes.




Bravo! How can we help this to happen?

Bill


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GlennLeDrew
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Re: unlearning the constellations new [Re: Plan9]
      #5485802 - 10/23/12 06:11 PM

Bruce,
Fine work on your galaxy map, based on the CO chart by Dame et al. I note the you missed two really nice OB groups; Cep OB 3 and 4. And it's worth pointing out that the Local and Per arm clouds, etc., between Cep and Gem are superimposed. The high latitude features tend to reside in our arm, while much of the stuff near the galactic equator is in the Per arm.


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cadfour
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Re: unlearning the constellations new [Re: Doc Willie]
      #5486803 - 10/24/12 11:04 AM

As a beginner in this hobby, last night rather than gaze at objects though the scope, I decided to take Bruces "big picture" approach. I looked at Sagittarius and thought...'Thats the center of our galaxy'....arced toward Vega and Cygnus and thought.....'Thats the direction our sun is moving'...then arced from Cygnus toward Orion and thought....'Thats the direction of the galactic arm that we reside'.

I think I might have gotten my first glimpse of the forest though the trees.


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uniondrone
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Re: unlearning the constellations new [Re: cadfour]
      #5487448 - 10/24/12 06:26 PM


Despite the contentions brought up in a few of the replies, I think that Bruce makes some fascinating points about how we look at the night sky and how this creates certain biases to our perspective of the universe. Although constellations can be useful navigational aids and have some historical and cultural relevance, we shouldn't overlook the fact that they are totally artificial constructs, lest we lose sight of the real shape and scale of our galaxy.


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Dennis_S253
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Re: unlearning the constellations new [Re: uniondrone]
      #5487687 - 10/24/12 09:28 PM

Cadfour, I think the center is in Scorpius. Between the arrow of Sagittarius and Scorpius's heart. And don't forget Ophiuchus, it's right there also.

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Dennis_S253
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Re: unlearning the constellations new [Re: Dennis_S253]
      #5487736 - 10/24/12 10:04 PM

I always wondered though, is the center the same in Africa or Russia or where ever you are? I suppose it must be.

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tedbnh
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Re: unlearning the constellations new [Re: Dennis_S253]
      #5487748 - 10/24/12 10:15 PM

I have not seen mention yet in this very interesting discussion of Guy Ottewell's "Astronomical Companion" in which he demonstrates with gorgeous hand-painted illustrations the 3D arrangement of nearby stars and DSO's.

So I will mention it! :-)

Also: When I explain the Messier objects to the public (what they are in general) I always try to point out that those hundred or so objects contain examples of almost every stage of stellar evolution and cluster life cycle in the rest of the Milky Way. It is just that we are lucky to have these examples close enough to see in small amateur telescopes. The message I try to convey is that they should try to understand that in the 95% of the Milky Way where we can't see such objects because they are too far away, it is almost certain that the same classes of objects occur everywhere. We got a nice random sample close to home, and since it's random it should be representative.


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derangedhermit
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Re: unlearning the constellations new [Re: drollere]
      #5488067 - 10/25/12 05:30 AM

Quote:

ptolemy represents a floor, not a standard. the point isn't that ptolemy is especially admirable ... it's that he at least saw the milky way as worth looking at, and that nobody since has looked at it with a comparable level of detail. (excepting things like the barnard survey photos ... one can find hundreds of lovely images, but a dearth of explanation of what we are looking at.)


There is often enough information to at least let inquiring minds take off in independent study - for example, each APOD photo, like today's Medusa Nebula, has a pithy summary of what we are seeing, with sufficient links to dig in further. But I suspect this is not what you mean.

Quote:

i claim there is a general lack of single and compact resources to anchor the average amateur astronomer's understanding of our place in the galaxy, its broad structure and processes.


I think you mean "broad" here quite literally, except limiting it to intra-galaxy size. Yet if I compare the scope of Shu, for example, in his textbook, then he spends a small fraction of his time on objects and processes focused on in this thread. He spends most of his time on smaller things (e.g. stellar development and evolution) and larger things (e.g. galactic dynamics). To me those other topics also deserve attention (or Shu seems to think so), and you are simply saying that the "average amateur astronomer" needs to have the equivalent of a year's worth of university-level coursework.

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Dennis_S253
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Re: unlearning the constellations new [Re: derangedhermit]
      #5488675 - 10/25/12 01:51 PM

We really don't even know what our galaxy looks like. It is people guessing. They don't know if there are 4 arms or 6 or 8. What size is it? Oh maybe 100000 to 120000 ly across and maybe 1000 ly thick. So, what do I do? I view the wonders of the universe with my small telescope and use my imagination. I personally don't care where it is. I'll never get to go there in person in this life. But as long as I know it's RA/Dec I can find it. We've come a long way I guess. Just how far, well your guess is as good as anybody's. In a very good dark sky you can see the galactic bulge. Well, thats what they think it is anyway. Has anyone or anything ever been there? NO

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csrlice12
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Re: unlearning the constellations new [Re: uniondrone]
      #5488837 - 10/25/12 03:32 PM

Quote:


Despite the contentions brought up in a few of the replies, I think that Bruce makes some fascinating points about how we look at the night sky and how this creates certain biases to our perspective of the universe. Although constellations can be useful navigational aids and have some historical and cultural relevance, we shouldn't overlook the fact that they are totally artificial constructs, lest we lose sight of the real shape and scale of our galaxy.




and the skies are not static, they are forever changing, albeit slowly. The sky of 100,000 years ago are not the skies we have today, and today's skies won't be the skies 100,000 years from now (and it may even be a lot shorter time period).


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Tony Flanders
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Re: unlearning the constellations new [Re: Dennis_S253]
      #5488889 - 10/25/12 04:04 PM

Quote:

We really don't even know what our galaxy looks like.




True.

Quote:

It is people guessing.




No, that's grossly overstating the case. We don't know precisely how our galaxy is constituted -- or any other galaxy, for that matter. But we have a pretty darned good idea. We do know it's a spiral, we're essentially certain that it has a central bar, and we have very tight constraints on the shapes on the arms and how stars inside them move. There's no doubt at all where the core is, nor is there any doubt about the central bulge.

This isn't guesswork; it's all based on solid observations.

As for the size of our galaxy, the uncertainty is as much a matter of definition as lack of data. Galaxies don't have sharp edges!

We can never know ANYTHING precisely, but that's no excuse for ignoring what we do know. If you don't want to learn, that's your own choice -- and your own loss. But don't blame it on lack of knowledge.

As for me, I find it odd when people aren't interested how they fit into the larger scheme of things, be that their family, their company, their city, their country, the planet, the solar system, the galaxy, or the universe at large.


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Dennis_S253
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Re: unlearning the constellations new [Re: Tony Flanders]
      #5488956 - 10/25/12 05:04 PM

True true and true. I for one does not have all the equipment one needs for sure. And if I were a younger man and knew what I know now, I may have had a totally different life. Most professional astronomer's spend very little time at a telesscope. Yes, I believe them when they tell me an object is X amount of LY's away. This universe is ever changing. Even our own asterism "the Big Dipper" is changing everyday. Yes, do I try to learn something everyday? Of course I do. But, I'll stick to being an amateur astronomer. I'll look for things in the night sky. Maybe I'll be the first to see a super nova or a comet or some other special thing. And when I do, I'll want to tell them what constellation it was in and what my RA/Dec was.

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GlennLeDrew
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Re: unlearning the constellations new [Re: Dennis_S253]
      #5489072 - 10/25/12 06:45 PM

Dennis,
By "sticking to being an amateur astronomer"', do you mean limiting yourself to looking skyward by peering into an eyepiece? Nothing at all wrong with that, but the definition of an amateur is in no way restricted to just gazing.


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Dennis_S253
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Re: unlearning the constellations new [Re: GlennLeDrew]
      #5489142 - 10/25/12 07:29 PM

True, there are amateur astronomers that do more than just gaze at the sky. Maybe there is no exact definition to use for myself. Back yard gazer who likes to look at a number of different objects?

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drollere
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Re: unlearning the constellations new [Re: GlennLeDrew]
      #5490006 - 10/26/12 10:57 AM

Quote:

Fine work on your galaxy map, based on the CO chart by Dame et al. I note the you missed two really nice OB groups; Cep OB 3 and 4. And it's worth pointing out that the Local and Per arm clouds, etc., between Cep and Gem are superimposed. The high latitude features tend to reside in our arm, while much of the stuff near the galactic equator is in the Per arm.




thanks for the kudos, glenn. the exclusion of CEP OB3 and OB4 follows de zeeuw & alia (query "de zeeuw 1999" at SAO/NASA), who couldn't identify a moving group based on hipparcos data, which of course has a limited resolution of distant proper motions. apparently for that reason they don't address associations in CAS, GEM, AUR and CYG which i've excluded as well. (see also the RASC guide to the gould belt HERE, which similarly excludes CEP OB3 and OB4 and was written by ... glenn ledrew!)

however, to the earlier post about wanting to see the stars in an association, it's important to emphasize the associations that are visually striking or clearly related to other visible landscape features.

i mentioned earlier that the milky way is actually "transparent" in many directions, and for that reason we can see distant features in the perseus arm through features in the local arm. for me this is a major difficulty in helping someone visualize the structures presented to the eye only as a mottled "flat" band of light.


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drollere
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Re: unlearning the constellations new [Re: derangedhermit]
      #5490097 - 10/26/12 11:57 AM

Quote:

Yet if I compare the scope of Shu, for example, in his textbook, then he spends a small fraction of his time on objects and processes focused on in this thread. He spends most of his time on smaller things (e.g. stellar development and evolution) and larger things (e.g. galactic dynamics). To me those other topics also deserve attention (or Shu seems to think so), and you are simply saying that the "average amateur astronomer" needs to have the equivalent of a year's worth of university-level coursework.



first off, i have to highlight your mention of frank shu's FABULOUS TEXTBOOK and my strong recommendation that anyone interested in the fundamentals of astronomy (and comfortable skipping over any unfamiliar calculus to follow the main story) should definitely snag a copy. it appears to be back in print.

i think you underestimate how closely my proposal complements shu, or at least would try to anchor his chapters 8, 9, 11 and 12 in visible structures. as i said earlier, the amateur astronomer can greatly benefit from the "landscape" awareness that our galaxy ("The Galaxy" as it's often called) has a certain size, shape, basic structure and motion, our place in that structure and motion, and the bright stars, asterisms or distinctive milky way features that locate all that in the sky.

all that is taxonomic: the real point is that we reside in an enormous machine for making stars, or more accurately star systems -- double stars and planetary systems. this is a *process* story that comes naturally out of the landscape. as i said, the whole story is laid out in almost any seasonal quadrant of the milky way -- silhouetted giant molecular clouds, bok gobules or barnard objects; illuminated H-II regions; massive OB stars and smaller T Tauri stars emerging from dust clouds or H-II regions; hot young star clusters like the double cluster or pleiades, cool old clusters like the hyades or praesepe, the rich mixture of main sequence, giant and white dwarf stars they contain -- what the difference between the clusters illustrates about their age and stellar life cycles -- supernovae remnants and planetary nebulae.

if all that stimulates questions of "why?" or "how?" then there is a firm basis to dig into shu's two protagonists, universal gravitation and the second law of thermodynamics, and how their fierce struggle plays out in structure and process. the foundation is laid.


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drollere
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Re: unlearning the constellations new [Re: Dennis_S253]
      #5490150 - 10/26/12 12:37 PM

Quote:

I for one does not have all the equipment one needs for sure. ... Yes, I believe them when they tell me an object is X amount of LY's away. This universe is ever changing. Even our own asterism "the Big Dipper" is changing everyday. Yes, do I try to learn something everyday? Of course I do. But, I'll stick to being an amateur astronomer. I'll look for things in the night sky.



i'd emphasize that the necessary equipment assumed here is your naked eye observation or, even better, a good binocular -- and a reasonably dark observing location, which for many is the most difficult bit of "equipment" to obtain.

of course the equatorial coordinate system is useful to align your telescope: i'm offering the galactic coordinate system, which is useful to align your insight. it's simply the center line of the milky way band; you can mark off the compass points positions with bright stars: N is the teapot, NW is altair, W is deneb, SW is the double cluster, S is beta aurigae, SE is sirius, E is lambda velorum, NE is alpha centauri. where is the galaxy center? N. where is the orion arm? from W to SE. where is the sun headed? W by NW. where is the scorpius-centaurus association? from N to NE. and so on.

it's perfectly fine to learn that "M45 or the seven sisters is an object in the messier catalog, located in the shoulder of the Bull, an ancient zodiacal constellation that appears in the art of minos and the myths of babylon."

i'm suggesting that you can with no more difficulty learn that "M45 is a very young star cluster located in a nearby area of the galaxy where stars are still being formed, probably a sibling to the cluster of stars around alpha persei and out of dark clouds of interstellar gas that are still visible in the milky way between betelgeuse and capella."

these alternative bits of "lore" have this effect: the question "how do we know, in the myths of *babylon*?" takes your curiosity in a very different direction from the question "how do we know, a *young* star cluster?" it's my contention that one question takes you further into the heart of astronomy, and the other question takes you ... somewhere else.


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auriga
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Re: unlearning the constellations new [Re: drollere]
      #5490638 - 10/26/12 05:58 PM

Sky Safari Pro shows the galactic equator very well.

How do you know the Teapot is North? On Earth what we have decided to call North is defined by the North Pole (rotational north) or by the North Magnetic Pole.

Isn't the direction you designate as North, namely near the Teapot, arbitrary for our galactic system? Why not call it South, East or West?

If one means the pole around which our galaxy rotates, the North Galactic Pole, on my maps it is in Coma Berenices, not near the Teapot in Sagittarius.

Please say more on these topics.

I am interested in learning more about thinking in terms of galactic coordinates, but I consider the history of the constellations in various cultures to be a very interesting part of astronomy.

Given the intellectual power manifested in your web site, you might enjoy Jacques Ellul's book, "La Technique" (title mistranslated as "The Technological Society.")

Thanks


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GlennLeDrew
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Re: unlearning the constellations new [Re: auriga]
      #5490724 - 10/26/12 07:00 PM

Auriga,
Bruce was indeed transposing an arbitrary compass face onto the galactic equator, as seen from galactic north, or 'above.'

Bruce,
I'm quite familiar with the work of deZeeuw, et al, and have the paper you mentioned. (One of the investigators sent me a copy of the fine book he produced as his PhD thesis summarizing this and related material.)

In my RASC article I omitted all associations not believed to belong to the Gould Belt (as the latter was the subject.) But Cep 3 and 4, as well as Gem 1, are eminently observable and interesting with small instruments. Eventually my own web site will feature, among other stuff, an observer's guide to the Gould Belt and other associations.


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drollere
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Re: unlearning the constellations new [Re: GlennLeDrew]
      #5490976 - 10/26/12 10:28 PM

Quote:

In my RASC article I omitted all associations not believed to belong to the Gould Belt (as the latter was the subject.) But Cep 3 and 4, as well as Gem 1, are eminently observable and interesting with small instruments.



you raise an interesting point, namely -- which stars are in an association? setting aside that things sorta change as new methods are applied, i don't know of a "viewer's guide" to association members. you *can* find academic papers with exhaustive lists, but many members are lost in the field stars. what's needed is a star chart with group members labeled.

also, i've looked for but haven't found a finder chart for the hyades, praesepe and pleiades ... perhaps you know of one.

of course your paper was limited to the gould belt; i was tweaking you. but to the substance, i omitted associations not in de zeeuw because of their failure to confirm 6 nearby associations grandfathered in the literature. (i made one exception for the far group CYG OB2.) that was an insight into the status of associations that gave me pause.


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Man in a Tub
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Re: unlearning the constellations new [Re: GlennLeDrew]
      #5491010 - 10/26/12 11:06 PM Attachment (20 downloads)

Quote:

Eventually my own web site will feature, among other stuff, an observer's guide to the Gould Belt and other associations.




Please let us know when that mission is accomplished.

The following parenthetical comment is all there is in the Hayden Planetarium's Digital Universe Guide.

Quote:

(The Gould Belt is a grouping of bright stars inclined to the Galactic plane that demonstrate recent star formation.)




A little skimpy. However, you can display something of the Gould Belt in a box.

(OK! OK! Just another plug for Digital Universe.)


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Dennis_S253
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Re: unlearning the constellations new [Re: Man in a Tub]
      #5491064 - 10/26/12 11:58 PM

Todd, how do you like this? I have seen this mentioned before. I guess u just start by downloading the atlas?

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Man in a Tub
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Re: unlearning the constellations new [Re: Dennis_S253]
      #5491174 - 10/27/12 03:09 AM

Get the "uncut" version for either Windows or MAC. Unzip to some location on your computer, e.g., "My Documents" in Windows. No installation needed. You run everything from the inside the unzipped folder. Follow the instructions/tutorials in the Digital Universe Guide.

Since 2005, I've downloaded several updated versions. Don't let the GUI put you off. The more you learn from the DU Guide and the Partiview User's Guide, the more you will enjoy the entire package! The Partiview User's Guide teaches you more about the Parti(cle)view(er) program that runs the 3D datasets.

There are only 100,269 stars in the Milky Way Atlas. Doesn't seem like a lot? I have a new computer and still can't display all 100,269 stars smoothly! There are commands to reduce the number of stars displayed.

The image I posted is full screen mode. The Partiview User's Guide tells you how to do this.



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DarkSkys
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Re: unlearning the constellations new [Re: Man in a Tub]
      #5491189 - 10/27/12 04:05 AM

coolio, just downloaded that. I've seen animation's done useing that, but I never knew were it came from.

Edited by DarkSkys (10/27/12 04:37 AM)


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Tony Flanders
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Re: unlearning the constellations new [Re: drollere]
      #5491235 - 10/27/12 06:48 AM

Quote:

You raise an interesting point, namely -- which stars are in an association? ... you *can* find academic papers with exhaustive lists ...




Actually, what I usually find is academic papers arguing with other academic papers about which stars are members -- and for that matter, about how many different associations there really are.

Membership of star clusters is already a vexed subject, and associations are an even looser concept than clusters. It's fairly easy to make broad statistical statements, but often impossible to pin down the information for one particular star.


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CounterWeight
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Re: unlearning the constellations new [Re: Tony Flanders]
      #5496116 - 10/30/12 12:35 PM

Hmmm After maybe 30 or so years in the hobby I had my decks cleared of most infomation by virtue of several brain strokes which left me quite diabled for several years. Astronomy is one of the few hobbies i am left to do now that I am as recovered as I can hope.

I sort of bristle a bit when anyone has something negative to say about mentality and GOTO and the hobby. I've never felt pinhole vision or reduced by it or anything else. GOTO works because there is a reference system. Funny that a converstaion about referece systems might start by slighting one that is so extraordinarily useful to so many from professional to child looking at a star chart.


I've never learned the constellations directly, don't see them as connected to astrometrics, astrophysics and cosmology at all except in an almost abstract sense. In determining location, apparent and so called 'proper' motion it more about spectra / magnitude and co-ord's as measuread at various times and places. As we get more information and better instrumentation the half life of 'facts' increases in proportion, or evaporates entirely.

Visually... Arc to Arcturus and speed on to Spica... this points at that and there is something interesting near there has always been my mode. Odd rhomboids or triangles pointing to others. I remember finding humor in folks that did know the constellations (somewhat) visiting first really dark skies and being somewhat confused, just too many stars

In ways I had no idea just how much I had tucked away until after my strokes and it was nearly all gone. Like a well known book and you turn to a favorite chapter and the pages are all blank. So I began again... here is where the planets transit, here is where the (i cannot actually see it from my white LP zone) disk of the galaxy is... that big square has pointers to that triangle... and there is M13!


Much of what we think we know is built upon reference systems of one sort or another and the methodology and classification criteria we build from these is copious. A good example of the transient nature of this is the thinking on quasi stellar sources over the last 40 years starting with their somewhat accidental discovery.

Going from very large scale to very small scale we indeed must use pinholes at times, if we need to be extremely precise, if that is the goal - as there are always folks that feel compelled to say things and it's the reference systems used that allow them to communicate about those objects and their relationship to other objects. So we have a need for perhaps more than one system of reference, but I for the life of me do not understand how RA and DEC or parsec/angle somehow hobble the amature astronomer (or professional for that matter). A reference system, if it is used in a motor driven computer or setting circles and paper charts is in many ways far more a help than a hinderance. I greatly prefer it to the somewhere in Orion approach, though if using binoc's or hand pointed scope "in the sword in Orions belt" is more than adequate assuming the person I am talking to understands what I mean by Orion and etc... same can be said for the spout or handle of the teapot? So in a sense you have to consider what is adequate to the task at hand? Here I refer to those often Arabic names and (at least for those of us in the west?) constellations that were and are quite useful for guiding across a desert with few landmarks for reference, and found equally useful by mariners transiting large bodies of water with sextant and clock.


I heartfelt agree that from a dark site, much becomes obvious in light of what those with a large scope and pinhole mentality - like Shapley - have contributed. From regions with LP issues (where most humans reside) it is 'IMO' at best a bit abstract even with some assistance by way of images, charts. Some classification schemes are a bit broad side of the barn like that of constellations, others like the H-R diagram a bit less so, and IMO the least arbitrary is the most precise which in many ways tells us the least - and that is the 'were exactly' in spacetime as we communicate about it. I don't think of it easy at all to do if I step back and consider what it took to get here.

I certainly am not recommending to have several brain strokes to really clear the boards as a good place to start. But I think whatever works for the task at hand is useful enough, whatever it might be.

Looking at anything with telescope or binoculars... easy to do? Posting it here on the internet with our computers and broadband providers? ... having the leisure to do so...

There are millions out there scrambling to get something to eat, and worse... count your blessings -I do.


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derangedhermit
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Re: unlearning the constellations new [Re: CounterWeight]
      #5496443 - 10/30/12 04:17 PM

The current observing forums here at CN:

NEO(Near Earth Objects)
Planetary and Solar System Observing
Lunar Observing
Deep Sky Observing
Double Star Observing
Solar
Variable Star Observing and Radio Astronomy

Or, grouped by distance:
Solar System:
- Solar
- Lunar
- NEO(Near Earth Objects)
- Planetary and Solar System Observing ("Solar System Observing" being "everything else" I guess

Milky Way:
- Double Star Observing
- Variable Star Observing and Radio Astronomy
- Deep Sky Observing

Extra-MW:
Deep Sky Observing
(Variable Star Observing and) Radio Astronomy

You could split "Deep Sky Observing" into "Milky Way" and "Other Galaxies", I suppose, to make more of a distinction and "make room" for discussion of the various local dark clouds and star groups. Other than that, the only overlap is in Radio Astronomy.


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drollere
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Re: unlearning the constellations new [Re: Tony Flanders]
      #5499379 - 11/01/12 12:49 PM

Quote:

Membership of star clusters is already a vexed subject, and associations are an even looser concept than clusters. It's fairly easy to make broad statistical statements, but often impossible to pin down the information for one particular star.




yes, that's fair, and it's one aspect of the general problem that the galactic structure at almost any scale is very difficult to examine beyond the local neighborhood. and as i said, the fact that de zeeuw et al. reject six traditional associations as lacking a common proper motion put me on guard to treat the more distant associations skeptically.

this discussion spins off the wish of one poster to observe (look at, visualize) the members of an association. nobody ignores open clusters because they are hard to inventory ... my theme is that nearby associations, like nearby open clusters, are not part of the average astronomer's mental map of the Galaxy and our place in it. it's more likely to be an enormous roof with quaint mythical figures pasted on it, each figure ornamented here and there with the pinpoint locations of tiny specific objects.


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drollere
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Re: unlearning the constellations new [Re: CounterWeight]
      #5499586 - 11/01/12 04:19 PM

Quote:

I certainly am not recommending to have several brain strokes to really clear the boards as a good place to start. But I think whatever works for the task at hand is useful enough, whatever it might be.




counterweight, i enjoyed your dissent and the fact that your health issues don't seem to have impaired your verbal skills. best wishes to you.

but, like others, you seize on the wrong end of my argument.

i am at present primarily a double star astronomer, and there is no way i could productively observe those critters without a reliable GOTO and equatorial coordinate system.

i also grew up in the era of Cave telescopes and i firmly believe that starhopping is an essential observing skill and a very effective route to learning the place and shape of asterisms -- not the ridiculously cobbled stick figure myth markers but all those simple geometric forms and angles that allow you to find something you can't see in the finder with visible stars -- that "Y" of naked eye stars that brackets M31, for example, or the curve of stars that leads to M11.

and of course ... why are we looking except to look *at* something significant. the fact that the "something significant" is visually very small means we need a telescope and examine a very tiny area of sky, one area at a time. so there is nothing misplaced in any of that.

but by "bristling a bit", you seem to have overlooked my four key points:

1. for many amateur astronomers, even relatively advanced astronomers, tiny objects distributed inside tracts of constellation real estate is "all there is". that is fundamentally how most astronomers conceptualize the contents of the sky.

2. if any amateur astronomer wanted to go "beyond the constellations", or "unlearn the constellations" (so that the visual sky could be organized with explicitly astronomical or physical concepts), there is a dire paucity of reference material to help him (with gratitude to the posters above who have pointed to a few exceptions).

3. worse, the lack of resources, and the constellation constriction in the standard literature, teach the amateur astronomer, explicitly, that "this is the only way," that there really *isn't* any other meaningful way to organize astronomical lore: learn the constellations, learn the messier list (and the silly names that go with it -- "owl," "crab," "wild duck," etc.), and be satisfied.

4. which is too bad, in my view, because knowing the galactic landscape leads you naturally into fundamental questions about galactic structure and galactic processes; knowing the celestial myths takes you into cultural archaeology, comparative religion, and 17th century celestial iconography.

our eyes look at the hubble images, but our heads organize the images with nothing more sophisticated than bayer's uranometria. the first step is to discard uranometria, unlearn the myths, and approach the sky with fresh and uncluttered eyes.


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Tony Flanders
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Re: unlearning the constellations new [Re: drollere]
      #5499647 - 11/01/12 05:15 PM

I think you're conflating two utterly distinct issues.

First, you're urging people to go beyond the 2-dimensional appearance of the sky and grasp the true 3-dimensional distribution of the objects that you're seeing -- and what it signifies.

I completely agree. Though it's worth remembering that there are actually two utterly distinct 3D structures out there -- our own galaxy and the clusters, strings, and filaments on which it and the other visible galaxies hang.

Second, you seem to have a specific animus against the traditional constellations as a means of organizing the 2-dimensional apparent sky. Frankly, I think that's a bit frivolous.

Yes, the traditional 48 or 49 constellations are mostly quite arbitrary, and the 40 newcomers are, by and large, much more ridiculous still. However, they're what we've got, and they're not about to be replaced -- any more than the ridiculous spelling of the English language is about to be rectified.

It's all very well to go beyond the 2-dimensional apparent sky, but before you go go beyond it you have to learn it. And that requires some organizational structures. I certainly have some private organizational structures all my own, but it's mighty handy to share some with every other stargazer in the world -- which I do via the 88 constellations.

Moreover, the constellations are dignified by their truly immense history. If they were good enough for Ptolemy, Galileo, Newton, and Herschel, they're good enough for me.


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Crossen
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Re: unlearning the constellations new [Re: Tony Flanders]
      #5499715 - 11/01/12 06:47 PM

Unfortunately the books most of us began our astronomical adventures with taught us the constellations through the associated Graeco-Roman astro-myths. However, most of those myths were created to explain what was already in the sky because about 60% of the 48 Classical constellations were inherited by the Greeks from the earlier Sumero-Babylonian civilizations of Mesopotamia. The early Greeks did do some of their own constellation invention: in particular, some of the constellations of the Perseus-Andromeda and Argo groups are Greek innovations. However, the majority of the constellations even in those two groups have Mesopotamian antecedents.

Because most of the Mesopotamian constellations we can identify seem to have been organized in the early 3rd and the 4th millennia BC, it is difficult or impossible to know why most of them were formed. Certainly many of them reflect early Sumerian religion. However, soon after they were invented, the Sumerians placed the 4-wheeled wagon, the 2-wheeled chariot, and the plow among the stars--which had nothing to do with religion.

Moreover, the earliest constellation lists we possess from Mesopotamia, which were written down in the centuries around 2000 BC, were NOT organized according to religious or mythological criteria. They begin with the Pleiades, which were simply called "The Constellation." Then comes the Pole Star. Then comes a section of planets and constellations with bright stars: Venus, Sirius, Orion, Centaurus, Taurus. (Of course I use the Classical, not the Mesopotamian, names.) Then follows a group of three constellations with names preceded by a determinative meaning that they were objects made of wood: the Plow, the Wagon, and the Chariot. Finally there is a section that lists several constellations in basic west-to-east order: specifically Corvus, Hydra, Libra, Scorpius, the Altar, and Sagittarius (with a couple groups interjected).

Thus these lists are ordered by a mixture of lexicographic and astronomical criteria--NOT by religious or mythological criteria. They represent the effort to see the heavens according to intellectual principles. Indeed, they are truly scientific documents, because the beginning of true science is classification (species in biology, rock-types in geology, clouds in meteorology) and organization.

The constellations therefore are an integral part of the history of the science of astronomy. Tony is right: when we use them we are simply following in the footsteps of great early astronomers like Eudoxos, Hipparchus, and Ptolemy. What we should "unlearn" is not the constellations themselves, but the historically inaccurate idea that the constellations are merely residuals of ancient religion, mythology, and superstition, inaccurate notions that have been perpetrated by older writers of introductory astronomy guidebooks who themselves seem to have been ignorant about the true nature of constellation history and Mesopotamian civilization.

Craig Crossen


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GlennLeDrew
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Re: unlearning the constellations new [Re: Tony Flanders]
      #5499824 - 11/01/12 07:57 PM

Bruce,
DeZeeuw and gang didn't reject more distance associations because of lack of common proper motion. There was in at least some cases sufficient commonality of motion. Rather, their work also relied on parallax measurements (from Hipparcos) for the determination of space motion. Beyond some 600 pc, the errors on the parallax were too large.

If and when the ESO's Gaia mission gets going, the two orders of magnitude improvement in astrometric accuracy will inaugurate a revolution in spatial mapping and dynamics.


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MikeRatcliff
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Re: unlearning the constellations new [Re: Crossen]
      #5499829 - 11/01/12 08:00 PM

Just wanted to thank Bruce and the others for this fine thread! One of the best I've read.

I'll mention Atlas of the Universe as a source that has helped me see how things are organized.

www.atlasoftheuniverse.com

Mike


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Plan9
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Re: unlearning the constellations new [Re: Tony Flanders]
      #5499921 - 11/01/12 08:58 PM

Quote:


Second, you seem to have a specific animus against the traditional constellations as a means of organizing the 2-dimensional apparent sky. Frankly, I think that's a bit frivolous.




"Animus" sounds harsh, Tony. I took it that Bruce's complaint (if you want to even call it that) was that the current way of organizing things interferes with seeing them any other way. I was kind of imagining a new set of constellations that actually represent stars in proximity to each other; I wouldn't expect that to be as easy to visualize or memorize, but might be more instructive.

Quote:


If they were good enough for Ptolemy, Galileo, Newton, and Herschel, they're good enough for me.





Didn't Galileo rearrange our conception of the heavens? *

Bill

* OK, Copernicus first


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Dennis_S253
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Re: unlearning the constellations new [Re: MikeRatcliff]
      #5499976 - 11/01/12 09:32 PM

Hey Mike, thx for that link. Bruce, maybe we just don't speak the same language??? I am not hung up on the constellations. To tell the truth, I maybe know 15 or so. The only one that (to me) looks like anything is scorpius. I see that big tail with stinger and the claw. I'm not into the myth story's per say. Yes, I have heard a few. The thing that makes me wonder is "how" did the old ones get all there idea's? They didn't have light pollution, I don't think. And as some have said, from a dark sky there are so many stars that it is hard to pick out constellations. Orion is just a bunch of stars. Bright stars that make a pattern that is one of the most reconized. I'm sure that (I know) all them stars are not all associated with each other. They are however associated with Orion at this time. What it looks like 100,000 years from now??? I'm sure there are ways of finding out.

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Dennis_S253
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Re: unlearning the constellations new [Re: Dennis_S253]
      #5500019 - 11/01/12 09:56 PM

Also, how in your 3D, how do you show 2 stars, that are 2 degrees apart but, 1 star is 28LY away with a mag of 4.35 and a star 1000LY away with a 5.10 mag?

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drollere
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Re: unlearning the constellations new [Re: GlennLeDrew]
      #5501115 - 11/02/12 03:18 PM

Quote:

DeZeeuw and gang didn't reject more distance associations because of lack of common proper motion. There was in at least some cases sufficient commonality of motion. Rather, their work also relied on parallax measurements (from Hipparcos) for the determination of space motion. Beyond some 600 pc, the errors on the parallax were too large.

If and when the ESO's Gaia mission gets going, the two orders of magnitude improvement in astrometric accuracy will inaugurate a revolution in spatial mapping and dynamics.




glenn, i don't have the doctoral thesis, but the published de zeeuw paper states that only CPM was analyzed in the modified convergent point method (p.358) and radial velocities were not used in the "spaghetti method" because "high quality radial velocities are available only for a small subset of the stars" (p.359). they did use parallax to limit stars within a common radial distance, but in effect the allowed range is (reading from their graphs) 1.5 to 6 mas (~500 pc).

i agree: GAIA is an amazing technical ambition and execution, even with the limitations imposed by budget ... as you say it will give an extraordinarily refined view of the local Galaxy. and papers, papers, papers of analysis.


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drollere
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Re: unlearning the constellations new [Re: Tony Flanders]
      #5501173 - 11/02/12 04:07 PM

Quote:

You seem to have a specific animus against the traditional constellations as a means of organizing the 2-dimensional apparent sky. Frankly, I think that's a bit frivolous.

Yes, the traditional 48 or 49 constellations are mostly quite arbitrary, and the 40 newcomers are, by and large, much more ridiculous still. However, they're what we've got, and they're not about to be replaced -- any more than the ridiculous spelling of the English language is about to be rectified.

... Moreover, the constellations are dignified by their truly immense history. If they were good enough for Ptolemy, Galileo, Newton, and Herschel, they're good enough for me.




tony, i have to thank you for expressing with flair the point of view i called out in my point #3 above. the point of view that: the constellations are how we do things, they are the only way to do things, they are the only way we have ever done things, there is no other fruitful or useful way to do things ... so shut up.

yes, they're ridiculous, arbitrary and antique, but i've made them mine! so make them yours!

i can understand how young or novice astronomers might find that viewpoint intimidating, but to my old ears it is the familiar squealing argument that always greets the proposal for fundamental change. it is, in fact, as time hallowed and empty as the constellations themselves.

my "animus" is not against asterisms per se -- as i said, the whole point of "unlearning" the constellations is to free up the raw visual stuff in the sky so that it can be organized according to other principles and objectives. my "animus" is against the baggage that comes with the constellations. why learn to pick up and haul around baggage, when you'll just put it down later?

i'm proposing the next step in what actually has been a long term, incremental and perfectly reasonable process of constellation deconstruction, from babylonian symbols and uncanny supernatural entities to empty tracts of IAU real estate. in the modern era, constellations as lore, as figures, as myths, have no justifiable relevance to a basic understanding of our place in the galactic landscape. we may as well use galen to learn anatomy.

of course, as cultural history, as comparative religion, as the stuff of burnham raptures over old coins and flaking frescos, some people will find pleasure in the pursuit -- and as tristram shandy well said, everyone has their hobby horse, and they should be able to ride it as merrily as they please. just don't block the doorway to something different.

aside from my objection to your tone and obstructionist premise, i don't have any objection. that really is the point that you and others fail to concede. and that indicates that you cannot argue against my proposal in good faith. indeed, false argument is your game. i doubt that universal orthography and grammar have the same weight of tradition as the quaint pictorialism of antique charts, or that the history of mythical iconography is as "immense" as, say, the history of britain. but make those falsely grand arguments if you like -- others can use them to test their own gullibility.

all that points up the fact that i do not have a *substantive proposal* to replace the constellations, only a proposal in concept and in principle. but you're motivated to hinder rather than help, so that's not an objection that you're qualified to raise.


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derangedhermit
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Re: unlearning the constellations new [Re: drollere]
      #5501283 - 11/02/12 05:45 PM

Should it be based on the galactic coordinate system?

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mountain monk
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Re: unlearning the constellations new [Re: derangedhermit]
      #5501339 - 11/02/12 06:34 PM

"...papers, papers, papers of analysis."

According to Harvard Magazine (May/June, 2012), researchers in astronomy are generating 7,000 articles a month and one robotic telescope can generate 10-20 gigs of data a night. There is plenty to analyze.

An interesting thread. Thanks.

Dark skies.

Jack


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Tony Flanders
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Re: unlearning the constellations new [Re: drollere]
      #5501654 - 11/02/12 10:06 PM

Quote:

Tony, i have to thank you for expressing with flair the point of view i called out in my point #3 above. the point of view that: the constellations are how we do things, they are the only way to do things, they are the only way we have ever done things, there is no other fruitful or useful way to do things ... so shut up.




No, that's not what I said at all. What I said is that the constellations aren't going to go away, and if you think they are, you're deluding yourself.

You're welcome to smash your head against this particular brick wall, but it's your head that's going to suffer, not the wall.

This is largely because of human nature; we are a very conservative species. But the reasons go deeper than that.

Stepping back a bit and looking at the underlying reality, it's a fact that we're stuck with the 2-dimensional appearance of the celestial sphere. That is our direct perception; everything else is deduction. It is largely (not entirely!) accidental, but it's an accident of nature, not culture.

You can argue all you want that people ought to think of stars and deep-sky objects as existing in three dimensions -- which I entirely agree with. But you're still stuck with your eyes and your visual cortex, and they will see the stars as a celestial sphere whether you like it or not.

And a good thing, too! Remember, the celestial sphere is something you can explore first-hand. Distances to celestial objects you have to take on faith. How many amateurs are actually going to measure the parallax of individual stars?

I don't want anybody to learn science at the cost of losing his or her direct perception. When you see an ant, you should see an ant, not think of it entirely as a chemical factory, an element of a superorganism, or a collection of cells or molecules -- though it is all those things, too.

In order to talk about the celestial sphere, we need shapes and categories. The constellations may be arbitrary, but so will any other shapes and categories used for this purpose.

There is a reason that you don't have a concrete proposal for what to put in place of the constellations -- because there exists no rational and objective way to do the job that they do.

So in many ways doing away with constellations is even less plausible than spelling reform. It is in theory possible to invent a rational spelling system for English; this has in fact been done for other languages, such as Russian (long ago) and Turkish (very recently). The obstacles to this eminently desirable reform are social, not fundamental.

However, there is no rational way to organize the perceived celestial sphere, because it is in fact accidental and arbitrary.

So there's absolutely no benefit to abandoning the current system. Yes, it's irrational, but at least everybody agrees on it. The alternative is Babel -- 7 billion mutually incomprehensible irrational systems.


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jrbarnett
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Re: unlearning the constellations new [Re: drollere]
      #5501705 - 11/02/12 10:32 PM

bruce, have you played around with Stellarium (open source planetarium program)? There is a setting that allows you to choose different culture's starlore/mythology. It's interesting, for example, to see how the pre-Christian Scandinavians and Polynesians imagined the patterns in the stars. Not exactly on point, but nonetheless I think you'd enjoy playing around with it.

Regards,

Jim


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Kfrank
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Re: unlearning the constellations new [Re: drollere]
      #5501717 - 11/02/12 10:37 PM

Drollere,

I'll break with those to whom this an interesting thread and say, that to me, your whole thesis is one of the finest examples of sophistry that I have ever seen on Cloudy Nights.

Poster after poster has tried to rationally take issue with you and many of these have made very cogent arguments. Your response has always been to reply that you are misunderstood. Perhaps you might consider that if so many misunderstand you, you're not stating your case clearly, or perhaps that your case has no merit.

I'll go on record as saying that I might be able respond to you appropriately if I were able to understand your intent - which, I'm beginning to suspect is simply to provoke controversy. We call that "trolling" on the 'net.

Some of your points are well taken but you are arguing against the conventional and accepted way of things. IMO you are tilting at windmills. Others have granted the validity of (some) of your points yet you seem determined not to acknowledge this.


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auriga
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Re: unlearning the constellations new [Re: Tony Flanders]
      #5501891 - 11/03/12 01:15 AM

Tony,
This is a truly intelligent and clarifying post. Thank you.
Bill


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auriga
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Re: unlearning the constellations new [Re: Crossen]
      #5501904 - 11/03/12 01:30 AM

Hi, Craig,
Remarkable insight about the meaning of the Mesopotamian constellations. An entirely new idea to me, quite stimulating and eye-opening.
I look forward to your forthcoming book on Mesopotamian archeology, which I suspect will deal with some of these astronomical issues?
Regards,
Bill


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auriga
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Re: unlearning the constellations new [Re: jrbarnett]
      #5501916 - 11/03/12 01:46 AM

Tony,
Another truly excellent post. Your point about the celestial sphere being inherent in the way we see is a very good one. And I am fairly sure that a perceptual psychologist would say that it is somehow inherent to connect adjacent dots, hence constellation figures are likely to emerge.

An underlying problem I think is derogation of the cultural and of the humanities.

This derogation may be a result of the kind of education (and adulation) many technical people seem to receive.

I find technique fascinating and elegant and useful but not to the exclusion of history, culture, the humanities and the social sciences.

I urge people to take a look at Jacques Ellul's book, La Technique (the title is mistranslated as The Technological Society, doubtless for purposes of marketing).

Bill


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Crossen
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Re: unlearning the constellations new [Re: auriga]
      #5502079 - 11/03/12 08:59 AM

Quote:


An underlying problem I think is derogation of the cultural and of the humanities.

This derogation may be a result of the kind of education (and adulation) many technical people seem to receive.

I find technique fascinating and elegant and useful but not to the exclusion of history, culture, the humanities and the social sciences.




The problem is not only that many people in the hard sciences tend to associate the constellations with mythology and religion and other aspects of the humanities, but that they associate it with astrology. They are correct: the constellations were/are associated with astrology. But they must remember that chemistry and physics grew out of alchemy: even the sainted Newton practised alchemy. One must not judge a line of study by its parents or by the company it kept in its youth.

The purpose of my post about the Sumerian star-lists was to show that even in the 3rd millennium BC there were some very serious and unsuperstitious minds using the constellations they had inherited from their ancestors to see the heavens in a disciplined, organized fashion. Those lists are the beginning of true scientific astronomy. The second step was also taken in the 3rd millennium BC: Sumerian astronomers (they deserve to be called such) divided the sky into northern, equatorial, and southern bands. They called these bands the Stars of Enlil, the Stars of Anu, and the Stars of Enki after the weather-god, the sky-god, and the water-god respectively--but those were just names reflecting earlier traditions that associated some constellations in those areas of the sky with those particular deities. The bands were so precise that early German assyriologists argued to within a half-degree of exactly where the borders between the bands were.

Like you, I see in the present culture a tendency to denigrate the arts and literature. I also see in it a tendency to denigrate the ancients. Just because they didn't know as many facts as we do, doesn't mean that they were stupid and their writings and art and science should be disregarded. How many people today--even teachers of history--know that Phoenician mariners circumnavigated Africa before 600 BC, or that the Babylonians used the Pythagorean Theorem before 1800 BC?

The constellations are a link not only with the literary and cultural past of the human race, but also with its scientific past. One cannot claim to understand the history of astronomy without knowing the role the constellations played in that history. And this knowledge is relevant to the practice of modern astronomy because the methods and patterns of intellectual inquiry are constants. The ancients may not be able to teach us anything about the local spiral structure of our Galaxy, but they can still teach us how to think and how to research so we can learn more about that spiral structure.

Craig Crossen


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drollere
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Re: unlearning the constellations new [Re: Crossen]
      #5503716 - 11/04/12 10:45 AM

two "rebuttals":

Quote:

You can argue all you want that people ought to think of stars and deep-sky objects as existing in three dimensions -- which I entirely agree with. But you're still stuck with your eyes and your visual cortex, and they will see the stars as a celestial sphere whether you like it or not. ... There is a reason that you don't have a concrete proposal for what to put in place of the constellations -- because there exists no rational and objective way to do the job that they do. ... There is no rational way to organize the perceived celestial sphere, because it is in fact accidental and arbitrary. So there's absolutely no benefit to abandoning the current system. Yes, it's irrational, but at least everybody agrees on it. The alternative is Babel -- 7 billion mutually incomprehensible irrational systems.



i recall the point in spinoza where he states that, as "direct perception", the sun appears to be about 30 feet above our head. certainly there is nothing about the moon, as a "direct perception", that indicates its true dimension, which, after all, is going to be exactly the same dimension as the sun, since "direct perception" during an eclipse demonstrates that they are exactly the same diameter. and after all, based on "direct perception", didn't people believe for centuries that comets were an atmospheric phenomenon? -- until kepler disproved it? and, where does "direct perception" lead us but to the ptolemaic system, or the sun as somehow a large sphere of burning coal?

the whole argument based on "direct perception" is nakedly specious.

"no rational way to do the job that they do"? what "job" is that, exactly? the celestial coordinate system locates objects, scientific analysis defines their size and distance (within an order of magnitude), catalogs list their visual and physical attributes. none of that implicates "constellations" as an organizing principle. where is "constellation" in NGC, or WDS? the organizing principle, such as it is, consists of an IAU fiat implicitly organized around bright stars as markers of visual space.

my proposal is that the sky should be organized, intuitively and as a mental map, so that our place in the *galactic landscape* is readily understood.

the claim that "sagittarius is a centaur in a traditional region of the sky" and "the teapot pours hot water on the center of the Galaxy" are equally arbitrary, or equally uninformative, is a patently illogical dictat.

when it comes to dictat, i point to your use of "deluding yourself", "it's a fact", "you're still stuck," "whether you like it or not", "we need", "there exists no" and similar unilateral declarations of fact and tradition as a clear demonstration of my point #3 above.

Quote:

The constellations are a link not only with the literary and cultural past of the human race, but also with its scientific past. One cannot claim to understand the history of astronomy without knowing the role the constellations played in that history. And this knowledge is relevant to the practice of modern astronomy because the methods and patterns of intellectual inquiry are constants. The ancients may not be able to teach us anything about the local spiral structure of our Galaxy, but they can still teach us how to think and how to research so we can learn more about that spiral structure.



certainly, the study of the past, commonly denoted history or historical studies, is a laudable pursuit and a very interesting and culturally important domain of knowledge. it's just not astronomy.

or much of the history of astronomy: if you read hoyle (Astronomy), pannehoek (A History of Astronomy), or couper & henbest (The History of Astronomy), you'll find little reference to, or information about, "constellations". the pannehoek and h&b indexes do not even list the word, and hoyle gives the concept two pages -- one entire page as a tabulation of names and abbreviations. but according to crossan, these people "cannot claim to understand the history of astronomy"!

as for science itself: the first problem in astronomy, after marking time and direction, was predicting the location in the sky of the sun and moon, and the correlated problem of the timing of eclipses. pannehoek spends quite a lot of time on it, because those two problems are fundamental right up to the 19th century refinement of celestial dynamics. in those problems, single bright stars, not constellations, served as the measurement points for the trigonometric calculations necessary to measure right ascension in the long era before reliable clocks. individual stars, not constellations, accompany the first to latest steps in the science of astronomy. (if you believe my proposals arise from ignorance, you delude yourself.)

one does not denigrate the ancients if the ancients are not relevant to the purpose. and, as both a painter and a musician, no disparagement of the arts has any relevance here, except as an ad hominem.

front to back, false arguments are used to support opinion pronounced with the rhetoric of dictat and defended on the principle that "we've always done it this way."


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Re: unlearning the constellations new [Re: drollere]
      #5503845 - 11/04/12 12:18 PM

having clarified the false premises that underlie "objections" to my proposals, (which will nicely serve as grist for the first chapter of my forthcoming book, Unlearning the Constellations) ... let's address substantive content.

1. the sky, as visual data, can be organized to mark, reveal and hold in memory our place in the galactic landscape. this is the fundamental principle that guides concept formation and rejects irrelevant content.

2. we introduce basic concepts of galactic structure -- distance, dimension, gravity, rotation, spiral arm, stars, interstellar matter. the first objective is to locate ourselves within this "static" landscape.

3. for the sole purpose of location, we observe that the area of the sky is traditionally divided into ancient, completely arbitrary, jerrymandered and egregiously unequal tracts called constellations, by way of showing that they are inappropriate for further use to orientate, demarcate, or locate. so we "unlearn" them.

3. we use bright stars, the canonical points in the sky since ancient times, as our framework for orientation, demarcation and location. we adopt a subset of the 58 bright NAVIGATION STARS as the useful framework; we prefer the term "toward" as the locating preposition ("toward Arcturus") rather than "in" ("in Bootes").

4. we describe this selection of historically significant and visually useful bright stars in terms of distance, mass, spectral type and temperature, we note that mass is destiny in the domain of stars, and we note that these stars are all quite close to us, as galactic distance goes. we call the sphere that contains them all the Solar Neighborhood.

5. we locate by the expedient of giving each bright star its share of sky. boundaries are defined simply at the halfway point between two neighbor bright stars. everything closer to arcturus than to vega, or to arcturus than to denebola, is "toward arcturus". we locate bright stars, in turn, through the use of compact and easily recognized asterisms, open clusters and seasonal associations -- if it's winter, that must be sirius.

6. we observe that the sky is divided into three zones: a continuous band of light known as the Galaxy, and two very large dark areas, the North Window and the South Window. we correlate these apparent features with the disk structure and rotation of the Galaxy and our location within it.

7. we map the sky using galactic coordinates, where the disk defines an equator that is really a horizon. for visual orientation we present the sky within this framework, using a stereographic projection for charting purposes, and we draw the bright star regions within stereographic charts. the north pole is at the boundary toward denebola and arcturus, the south pole is toward diphda.

8. we briefly describe content as signs of structure: the galaxy is the most dense concentration of stars and interstellar medium, and therefore visually obscuring but also visually the direction of most bright stars. the windows are relatively free of obscuring matter and allow a view of the universe beyond the galaxy. we note that certain objects -- nebulae, open clusters, associations -- are concentrated within the galaxy zone, while other objects -- galaxies and galaxy clusters -- are confined to the windows. we introduce the concept of halo and disk stars, and the peculiar nature and status of globular clusters.

9. we note that, for the mechanical purposes of pointing and tracking from the surface of the earth, we must adopt a framework that is anchored in the Earth's rotation. we introduce the system of equatorial coordinates, and use it to indicate the inclination of the earth to the galactic disk. we note that this system is highly practical for mechanical purposes, and otherwise empty of content. finally we introduce the system of ecliptical coordinates, and use it to indicate the inclination of the solar system to the galactic disk. we use both systems to anchor the concept of a coordinate system in the fact of rotation or revolution, and underline the relationship of the galactic system to galactic dynamics.

10. we return to the solar neighborhood and identify the solar apex (toward vega), the differences between proper motion, radial motion and spatial motion, the spatial motion of the bright stars (speed, direction and variety), the effects of galactic rotation on their measured movement in relation to the sun.

11. we again use the bright stars (by repeating their study, we lead them into memory) to develop the concepts of absolute and visual magnitude, distance and brightness, distance and parallax, parallax and brightness (distance modulus). we develop the relationships of arcsecond, astronomical unit, year, parsec and absolute magnitude as a consistent set of concepts similar to the metric system. (we downplay use of the "light time" as a metric.) we explain the measurement of motion using aberration, doppler shift, astrometry, and parallax.

12. we expand from the solar neighborhood to explore the visible galaxy in detail. we identify the galactic center and its location to the teapot asterism. we define the local arm and its extent from deneb to sirius. we indicate the far arm as extending from altair to regor, and the outer arm from regor to sirius.

(the wife beckons to brunch and frolic. more shortly.)


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auriga
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Re: unlearning the constellations new [Re: Tony Flanders]
      #5504001 - 11/04/12 02:15 PM

Quote:

Quote:

I knew I should stay away from this. Starting with the title, "unlearning the constellations".




The title is probably unnecessarily combative. I think "Beyond the Constellations" would be more accurate.

For me, the greatest glory of astronomy is that there are so many different ways to approach it. There had better be! It is, after all, the study of the universe -- literally, everything that is, has been, or ever will be. I find the aesthetic approach, the historical approach, the study of individual objects and stars, and the study of how they fit together, all equally interesting.




Tony,
Here again I agree with you entirely. DJ is on to something when he suggests we observers should devote more attention to the organization of our galaxy, but his proposal to junk the constellations is needlessly provocative. What is needed is an additional way of observing and understanding , not a substitution for all other perspectives.

Blll


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auriga
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Re: unlearning the constellations new [Re: drollere]
      #5504060 - 11/04/12 02:59 PM

Bruce,
In my humble opinion your website shows you to be erudite and to have a really fine mind. Your writing shows a wry sense of humor in addition, in my opinion.

I look forward to your book , where you can spin out your ideas in more detail.

But I believe your book will get a better reception and be more influential if you avoid needlessly provocative formulations, and speak of changing our emphasis rather than junking the past entirely.

A problem for me is that I find your writing style in these posts to be highly aphoristic, and therefore enigmatic. For example, what do you mean by "dictat?" How do you know something is a dictat rather than an opinion or an assertion? In the book you will doubtless have more time to make clear what you mean by these aphorisms.

Your idea of science as disembodied from culture is for me an underlying problem. In my view science arises from culture and is best appreciated if one understands the culture that gives rise to science. For example, Karl Popper's ideas of "falsifiability" (disconfirmability), which are essential to modern scientific inquiry, arose from a particular historical and cultural and philosophical background. Richard Feynman's skeptical, playful and inquisitive approach to doing science arose from his personal and cultural background. Atul Gawande's methods of improving surgical practice arose from a particular historical and cultural context, as his books demonstrate.

I wish you best of success with your book,
Bill


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drollere
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Re: unlearning the constellations new [Re: drollere]
      #5504065 - 11/04/12 03:01 PM

13. we recall the practice of some south american cultures of naming and narrating the dark features of the Galaxy, which points to a clearer description of the Galaxy features and the obstacles to observing them. using wide field photography, we survey the Galaxy in panorama, noting the bright star markers for galactic coordinate "compass points". the survey also brings into focus several "marker objects" in the galactic plane.

14. we review the basic methods of radio, infrared and xray astronomy, the concept of marker objects -- molecular clouds, star forming regions, HII regions, galactic clusters, OB stars, globular clusters, and their spatial motions -- and the evidence they provide for galactic structure and our location within it.

15. we return to the Galaxy, now armed with a structural picture, and parse the visible Galaxy in terms of near and far features, obscuring clouds and long views, spiral arms and the spaces between them.

16. we address the Galaxy as process, again returning to the system of bright stars, and use them to narrate the development (not evolution) of stellar objects.

17. we expand process to include star formation and collapse, linking together molecular clouds, star forming regions, HII regions, galactic clusters, OB stars and associations, and planetary nebulae within the dimensions of time, mass and space. all traditional messier, galactic NGC target objects are located within this single sequence, and attributed an age. in particular, we explain the use of the HR diagram to "age" clusters.

18. we digress from this expanding grand view to consider mass segregation, mass biasing and mass luminosity, once again to return to the bright stars in the solar neighborhood, this time to look at the initial mass function, stellar populations, and planetary systems. we update the drake equation to demonstrate that "intelligent life" as a technical civilization is most likely quite rare -- probably no more than half a dozen across the entire Galaxy.

19. we turn next to the north and south windows, explain how the stellar population there differs from stars in the galactic zone, and in particular how this region is populated with low metallicity stars and globular clusters. we link these facts to galactic formation and evolution, the capture of "dwarf" systems such as the magellanic clouds, and the process of element formation.

20. we conclude with the far view available through the windows, and the structures that appear there. we note the galaxy clusters that appear toward denebola, toward the dipper, toward spica, and toward diphda, fomalhaut, ankaa and achernar. we note the microwave anisotropy, our near galaxy neighbors (toward mirach and canopus), and outline galaxy superclusters.

Epilogue. we make a few general observations about astronomy and the great physical processes it reveals to us. we summarize the major themes of question and inquiry that have shaped the development of astronomy, and the importance of these to the Enlightenment and the formulation of scientific practice today.

we end with a problem: light pollution and the vast blotting out of the sky that is a fundamental feature of modern civilization. and a question: how has that problem arisen, and what does it signify about our technology? we discover that the remote places that reveal the sky, and the lore that clarifies its significance, both suggest that change is needed in how we look at the sky, and how we live on the Earth.

###

these posts provide an off the cuff outline; i'll return to each "chapter" in more detail as i have time available.


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Glen A W
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Re: unlearning the constellations new [Re: drollere]
      #5504088 - 11/04/12 03:20 PM

I have been at astronomy for 25 years and I consciously did not learn constellations until about 2008..... because I thought they were a contrivance. After I became almost a "full time amateur" for a while, I did learn them, but I realize now I have installed something artificial into my mind, though it is not unpleasant to study the mythology behind constellations.

I liked your pictures you posted.

GW


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drollere
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Re: unlearning the constellations new [Re: auriga]
      #5504122 - 11/04/12 03:35 PM

Quote:

A problem for me is that I find your writing style in these posts to be highly aphoristic, and therefore enigmatic. For example, what do you mean by "dictat?" How do you know something is a dictat rather than an opinion or an assertion?



though possibly considered unusual, dictat is by no means obscure, since journalists (!) seem to favor it: see here ...

http://www.telegraph.co.uk/finance/comment/james-quinn/9261801/Europes-dictat...

and HERE.

i briefly collected (above) some of the "dictating" phrases tony seems to use without blushing, but if you carefully read his post you can discern his premise that "i'm telling you how it is (you're stuck with it), you're nuts if you contradict me (it ain't gonna change)."

Quote:

Your idea of science as disembodied from culture is for me an underlying problem. In my view science arises from culture and is best appreciated if one understands the culture that gives rise to science. For example, Karl Popper's ideas of "falsifiability" (disconfirmability), which are essential to modern scientific inquiry, essential arose from a particular historical and cultural and philosophical background. Richard Feynman's skeptical, playful and inquisitive approach to doing science arose from his personal and cultural background. Atul Gawande's methods of improving surgical practice arose from a particular historical and cultural context, as his books demonstrate.



bill, if you have missed the point that i want to create a system of astronomical description that makes very clear the underlying facts of astronomy, and by that process brings science more clearly into the common sense and commonplace knowledge of astronomers, then please help me edit my posts to make that objective very clear, since it is at the heart of my motivation.

to say, as crossan does, that we should preserve the lore of three millennia previous because it is science, or shows how science is done today, is factually false. of course i could reply that science as practiced today requires (among other things) material causes, replicable demonstration and peer review, when the babylonians worked from spiritual causes, cookbook methods and priestly secrecy -- but crossan's premise is emotional and nostalgic, and bringing facts against it is pointless.

to your view that "science arises from culture," i'd rather say that it is actually "science" that has been jeopardized by a focus on the past, and by "cultural" abuses related to the defense of personal prejudices, corporate interests, academic status, political gain and religious beliefs. it's really science that is being derided and denigrated in our culture, while the "arts" of music, theater, painting, film, comedy, rhetoric, grooming fashion and investing that are cultivated and celebrated -- often as lucrative markets and shaped by profit motive.


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Re: unlearning the constellations new [Re: Glen A W]
      #5504136 - 11/04/12 03:45 PM

Yes, the constellations are an artificial contrivance. But, they represent a reasonable and accepted way to order the night sky. The ancients did indeed view the night sky as a ball on the inside of which the stars were "mounted". I don't think there are any folks here that conceptualize the skies in that way.

And yet, the system we use today for locating celestial objects (RA and Declination) is simply a grid, drawn on the inside of the ball that the ancients believed in. We keep it because it works.

I could make a reasonable case that, if we scrapped the notion of man-made boundaries on the planet Earth and eliminated the notion of Nation-States we would open ourselves to a better understanding of the nature of our planet and of humanity. But, 'tain't going to happen any more than we're going to abandon the constellations as a map to learning the sky. I have no problem with "abandoning" the concept of constellations as mythical figures in the sky but there's no way you'll convince me that one cannot use the constellations as points of reference while also appreciating the complexity of the universe and working toward a better understanding of the true nature of the cosmos.


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auriga
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Re: unlearning the constellations new [Re: Glen A W]
      #5504543 - 11/04/12 08:48 PM

Bruce,
Your 20 points are very clarifying. It might be good to start with them in your book.
Bill


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auriga
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Re: unlearning the constellations new [Re: drollere]
      #5504584 - 11/04/12 09:18 PM



to your view that "science arises from culture," i'd rather say that it is actually "science" that has been jeopardized by a focus on the past, and by "cultural" abuses related to the defense of personal prejudices, corporate interests, academic status, political gain and religious beliefs. it's really science that is being derided and denigrated in our culture, while the "arts" of music, theater, painting, film, comedy, rhetoric, grooming fashion and investing that are cultivated and celebrated -- often as lucrative markets and shaped by profit motive.





Bruce,
Have you thought of reformulating the above as follows: There is certainly a denigration of science in our society if we discount vague praise and pay attention to scarcity of funding for scientific research and for the teaching of science on the primary, secondary and university levels.

There is also a denigration of the cultural, the humanities, and the social sciences, measured by funding and by stinginess of salaries of teachers in those areas.

The source of the denigration is our exaltation of materialism, our greed, our winner-take-all approach to corporate compensation, and our substitution of infantile music and vulgar reality television for the arts and literature.

I do think it impairs your presentation to conflate the humanities and the social sciences with greed and vulgar materialism, and I think distinguishing the two would greatly help your argument. You would then have obviated Tony and Craig's quite well-founded objections.

I look forward to your book. it obviously will be quite original, thoughtful, and probably erudite as well. I empathize a bit with your position since I have just completed an unorthodox book manuscript --perhaps not as erudite and original as yours-- in my case in the social sciences, and I am looking for a credulous publisher. Like you, I may get quite a bit of flak for my book.

Regards,
Bill


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Dennis_S253
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Re: unlearning the constellations new [Re: auriga]
      #5504632 - 11/04/12 09:40 PM

I wish you luck on your book also. Just don't expect me to buy it. We speak a different language. You don't understand me and I don't understand you. Clear skies...

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Glen A W
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Re: unlearning the constellations new [Re: Dennis_S253]
      #5505105 - 11/05/12 08:57 AM

Quote:

We speak a different language. You don't understand me and I don't understand you. Clear skies...




All the more reason why you should buy it! GW


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ohioalfa64
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Re: unlearning the constellations new [Re: Glen A W]
      #5505890 - 11/05/12 07:50 PM

Bruce,
Is there really a book in development, or is this an online essay in its final form?


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careysub
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Re: unlearning the constellations new [Re: drollere]
      #5506855 - 11/06/12 12:52 PM

Quote:

...
we all learn the constellations in our novice steps, and these ingrain certain asterisms in mind as if they are equally distant stars appearing at pretty much their absolute magnitudes. this is so far from the truth that it seems necessary to unlearn the constellations in order to make sense of the sky....




When I do outreaches one point I like to make (if they are visible) is to explain the random nature of most constellations, but then point out those that really are physically associated groups of stars, and what it is they are looking at (e.g Orion and the Orion-Eridanus complex; the Ursa Major Moving Group).


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drollere
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Re: unlearning the constellations new [Re: careysub]
      #5508418 - 11/07/12 01:59 PM

i spent the past few nights pursuing the issue of the bright "anchor stars" (per my outline posted above), simply looking at the sky with my eyes rather than with a telescope or binocular. these anchor stars are the starting point for several different avenues of inquiry ... but they need to be, first of all, easily recognizable and useful signposts to the solar neighborhood and galactic landscape.

this is a favorable time of year for the exercise, because the sky presents both many bright stars and a great variety of constellations, as indicated HERE.

my experience turned up the following insights:

1. "recognizing" the constellations is an act of constructive looking. if you simply turn toward a random area of sky (especially if you do not know the compass direction), a few moments of "study" are necessary to recognize the bright stars or asterisms, parse them as constellations, and "trace" them with the eyes.

2. the constructive looking often requires running your eyes over the entire figure, to "connect the dots" of the supposed asterism. this may not seem plausible with a bright or compact asterism such as orion or auriga, but try your luck with cepheus, pisces, aquarius or lacerta. you don't "see" constellations so much as "search for them".

3. taken by themselves, the bright stars define asterisms that are completely unrelated to the traditional constellation figures. the summer triangle (altair, vega, deneb) is a simple example. cygnus is really a "T" shaped asterism -- albireo is both detached and relatively faint. perseus is really a long arc of stars that naturally ends in the pleiades. andromeda is an arc of three bright stars (alpha, beta, gamma). the dipper is salient, and detached from the string of faint stars associated with it.

4. associating faint stars with bright stars seems to make the faint stars brighter. having traced the constellation outline visually (usually, three or four times), the gestalt tends to equalize the stellar brightnesses.

5. there are large gaps in the sky. the area from the pegasus square to diphda or formalhaut is basically empty. so is the area between the auriga pentagon and the dipper. you need dark skies to be able to see the stars in pisces or aquarius, much less trace them as "figures". once you let go of "constellations", these broad dark areas appear remarkable and mysterious.

the local arm presents a beautiful structural transition from deneb to betelgeuse, and, after you've done your naked eye assay of constellations, it's rewarding to scan this arc with a binocular. notice how the texture, density and brightness of the stars changes from the distant star clouds around albireo to the coarser, brighter star fields passing capella. as you do, note the changes in star density, brightness and the appearance of nebulae in relation to the locations of deneb, alderamin, caph, mirfak, capella, elnath and betelgeuse.

i regret i can't make similar observations about southern constellations, but it seems (as one example, and looking at star charts) that the four brightest stars in centaurus and crux form a natural group.

the goal here is to identify conceptually useful groupings of visually bright stars. i found it was actually a bit of concentration and patience to lose the ingrained habit of "seeing" what i have memorized. looking at the sky from different angles, sweeping broad areas or focusing on details, not looking at any specific asterism but taking them all in with indirect vision -- these techniques helped.


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drollere
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Re: unlearning the constellations new [Re: auriga]
      #5508446 - 11/07/12 02:26 PM

Quote:

I do think it impairs your presentation to conflate the humanities and the social sciences with greed and vulgar materialism, and I think distinguishing the two would greatly help your argument. You would then have obviated Tony and Craig's quite well-founded objections.



all i can say is, please read my four points in the post several posts above, and the twenty topic heads in the "book" outline. i don't see any substantive reference to humanities or arts in them.

the theme all along has been to organize our visual recognition of the night sky in a way that leads naturally and intuitively to a recognition of the structure of our galaxy and our place within it.

i have pointed out that the traditional astronomy literature and commercial astronomy guides perpetuate a way of looking at the sky that obstructs rather than facilitates that objective and encourage a fragmented and contextless understanding of astronomy.

all the posts that seek to drag this topic into other issues, are, as i've pointed out, unconstructive and based on poor evidence or faulty reasoning. but no matter. i feel i've been patient in replying to those concerns and, as they are irrelevant to my stated aim, i am not interested to address them further.


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auriga
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Re: unlearning the constellations new [Re: drollere]
      #5509097 - 11/07/12 09:52 PM

Bruce,
This quotation from your earlier post struck me as identifying the arts and the humanities with vulgar materialism:

"to your view that "science arises from culture," i'd rather say that it is actually "science" that has been jeopardized by a focus on the past, and by "cultural" abuses related to the defense of personal prejudices, corporate interests, academic status, political gain and religious beliefs. it's really science that is being derided and denigrated in our culture, while the "arts" of music, theater, painting, film, comedy, rhetoric, grooming fashion and investing that are cultivated and celebrated -- often as lucrative markets and shaped by profit motive."

I disagree with the above quotation and I contend that there is immense value in many things in our history and our culture that are not in themselves science. I think you do your argument a disservice by a needless explicit and implicit derogation of the arts, the humanities, history, and the social sciences.

But the idea of your book strikes me as original, and you are certainly knowledgeable the area of galactic structure, so i am hoping to find quite a bit of value in your forthcoming book.

I will let the matter rest here, and wish you well with your book..

Bill


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CounterWeight
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Re: unlearning the constellations new [Re: auriga]
      #5509712 - 11/08/12 10:50 AM

Bruce,

Thank you for taking the time responding to my post, I am grateful.

Quote:

our eyes look at the hubble images, but our heads organize the images with nothing more sophisticated than bayer's uranometria. the first step is to discard uranometria, unlearn the myths, and approach the sky with fresh and uncluttered eyes.





I am in agreement in many ways - I believe Steve O'meara says something quite similar in his 'Hidden Treasures' book - or at least very much along those lines. Having catalogs and objects that populate them, and not realizing that in the space nearby may be other interesting objects of one stripe or another.

I have encountered similar thinking in other works, though my memory issues prevent an exect recounting. Something ssems to tickle from Shapleys' "Inner metagalaxy" - a book I have 2 copies of and have not re-read in much detail since my gaskets blew out.

I do remember much discussion some time ago (70s?) when there was a large wall poster of a galaxy type as ours is proposed to be with a 'you are here' label / arrow out on one of the arms. Somewhat heated discussion /debate about it being fantasy as most of our galaxy hidden.

You make several points that I think in considering the significant increase in data over the last forty or more years have a lot of merit. Your points about star type / association / grouping - and visual cognition. As an exapmle you refer to Cyg as a 'T' shape and it certainly is ! to me it's back to back right triagles. I've never seen it as a swan or anything else. I suppose I could say same for the squares of Peg, Leo, Herc... Then ther's huge spanning associations I have like this morning Arcturus->Spica->Denebola-Regulus and much more...

As a point I'd like to add that it's quite interesting to look in Burnahms for interesting doubles, then same exercise in NSOG, then type in a search in SkyTools3 pro - and compare results. Not all the data is new but with modern computing the data is being collected and qualified and quantified, sorted, 'binned', and tagged. I'm a bit astonished how much data is available to me! And there are sites like this one which are very interesting.

I think I understand your point is one of both aspect and orintation? If I have that wrong I apologize. Here I am referring to our sun/earth and solar system orientation - then the night sky celestial orientation. I think it simple for folks to understand these days that the sun is on the other side and illuminating the moon and that the planets occupy a certain arc/plane in it as the earth spins and they orbit the sun. I'm using simple in a relative sense.

Plane of our galaxy being somewhat easy to explain at any dark site as it can be visualized and not a problem to state/see that it's the area we look for nebula and clusters and 'neighbors' in the plane. Looking out of plane we see much farther and other galaxies show up on the radar.

Plane of solar system not orinted same as galactic plane.

Here is where to me it gets a bit complicated from a historical perspective and in some ways might get interesting depending on how you look at history, and possibly what someone might believe about history. Here I refer entirely to the constellations of the Zodiac and nearby, not just the star associations used for terrestrial navigation. And here I am unclear on what and if any associations or dissociations are necessary and important. The question of arbitraryness comes to the front? For instance if I say the zodiac is arbitrary, am I then going to say the base x system of circular division also arbitrary? Why 360 deg divided into twelve secions of 30 deg?

Lets say... yes, discard it all. This only because we have a more useful system to replace it. We could conceive of using something based on magnitude / vector of stars relative to one another.

But to get away from a simple x/y orintation and into a vector system might be even more 'modern'. So we can also say goodbye to the Cartesian reference entirely and go to one based in three dimensions instead of two. I think at that point we have discarded all not required historical reference? This aside from re-naming the stars? Here the door opens to even more modern mapping and associations and we could possibly include more modern ideas about spacetime. If we include understanding of absolute and relative magnitude, direction of relative motion, distance and light travel time, area of 'mesh' wrt time and distance... there are many significant changes. We are then looking at the space map in a relativistic sense and not simply as navigators needing simple x/y co-ord's and a clock. IMO then we are looking as navigators of spacetime and not earth surfaces.

If that is the direction you are meaning it's certainly interesting to me.

My objection to discarding the historical perspective has much more to do with my appreciation of history and that what may seem arbitrary to us today in a practical sense still has significant meaning and relevance to our understanding of the great cultures, minds, ideas that brought our understanding and interests this far. I have more than once found myself nearly floored that ancient civilizations created systems that could work at all many thousands of years later, let alone be understood across numerical base systems, writing systems, to the point of inclusion and incorperation. I think that there is a historical perspective to it is hugely significant and important, a fantastic validation of some principals of mathematical and geometric thought.

So where does the historical practice/perspective participate to the point where it should inhibit moving something forward in a constructive sense? In a relativistic and cosmology mapping pretty much everywhere other than names (I think they are useful and practical even after stripping off most other things?)

Apologize for the long post, but just after some clarification in my own thinking in trying to understand the ideas/concepts of necessary and sufficient to create something truely new and useful and illuminating to anyone interested.

Also my apology for numerous typo's.


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drollere
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Re: unlearning the constellations new [Re: CounterWeight]
      #5510035 - 11/08/12 02:08 PM

i am certainly intrigued, even fascinated, by the sentiment repeated here that my proposal to look at the sky with fresh, wide eyes is equivalent to trashing the past, burning books, forbidding ideas, purging texts, policing speech or denigrating culture.

as i said, i decline the opportunity to debate those points further. but i appreciate the demonstration of the grip that tradition holds on the mind.


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Glen A W
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Re: unlearning the constellations new [Re: drollere]
      #5510054 - 11/08/12 02:22 PM

Quote:

i am certainly intrigued, even fascinated, by the sentiment repeated here that my proposal to look at the sky with fresh, wide eyes is equivalent to trashing the past, burning books, forbidding ideas, purging texts, policing speech or denigrating culture.




I think it's a great idea. And one whose time has come. GW


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drollere
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Re: unlearning the constellations new [Re: drollere]
      #5510076 - 11/08/12 02:42 PM

the next step, perhaps the most difficult step, is selecting out of the visible sky the features that can orient the observer and mark out the galactic landscape.

since constellations are by and large unsatisfactory as visual guides (as explained in the previous post), and asterisms have no content as structural features (the stars that compose them can be very widely separated in space), the objective seems to lead to a selection of visually bright stars as the solution space.

"bright" is a loose term (professional astronomers would call a magnitude 15 star "bright"), but given the limitation of naked eye orientation a magnitude cutoff of between 2 to 3 seems about right. for example, stars above magnitude 3 are relatively robust against urban light pollution. in cassiopeia, a salient constellation and asterism, four of the five stars in the "W" are above magnitude 3; similarly, in auriga, all five stars in the pentagon are above magnitude 3; in the dipper, six of the seven stars are above magnitude 3. in contrast, in cepheus, an obscure constellation, only alderamin is above magnitude 3; in lyra, another obscure constellation, only vega is above magnitude 3.

what would a list of "bright" stars, however defined, be used for? at least:

* for orientation to the night sky (e.g., season, sidereal time, direction, latitude)
* for orientation to galactic features (e.g., the galactic center, the local arm)
* as a descriptive sample: what kind of star is a typical bright star?
* as a representative sample: what does the population of stars look like?
* as an enumerative sample: what is a visible example of every kind of star?
* as a local sample: which stars are visible local stars (within X parsecs)?
... and so on.

this is a problem i am still working on. a magnitude cutoff between 2 and 3 seems useful, as it limits the number of stars in the list to around 100 or less. a distance cutoff of about 50 parsecs seems useful, as there are about 50 bright stars within that radius. but a preliminary look indicates that many of the late type (K or M) stars in that list are giant stars. and none of the stars within 50 parsecs is an early type (OB) giant star.

so the challenge seems to be this: develop an intuitive and consistent approach to the selection of landmark stars that are both near and far, intrinsically bright and dim, span the entire HR diagram, and point the way to galactic features ... not so easy, it seems.


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Dennis_S253
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Re: unlearning the constellations new [Re: drollere]
      #5510163 - 11/08/12 03:55 PM

Oh my gosh, the sky is wonderful.

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Tony Flanders
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Re: unlearning the constellations new [Re: drollere]
      #5510266 - 11/08/12 05:10 PM

Quote:

i am certainly intrigued, even fascinated, by the sentiment repeated here that my proposal to look at the sky with fresh, wide eyes is equivalent to trashing the past




Sorry, you are the one who said that it's helpful, maybe even necessary, to "unlearn" the constellations -- in other words, to trash the past.

Nobody has objected to your proposal to view the sky with fresh eyes, and many of us have enthusiastically embraced it. But you seem to be the only one here who finds that the old system obstructs the new one. Most of us have no trouble viewing reality simultaneously from multiple perspectives.

I never visualized the constellations as true physical entities, nor do any of the beginners that I speak to at star parties. In fact, one of the first questions I get is usually "Do those stars really belong together, or is that pattern an accident?" To which I reply, "an accident, of course."


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Dwight J
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Re: unlearning the constellations new [Re: Tony Flanders]
      #5510639 - 11/08/12 09:51 PM

"Unlearning" the constellations would essentially be equivalent to unlearning breathing - not possible. Our brain organizes randomness into patterns at an unconscious level. When I look up, I can't stop seeing patterns and shapes defined by the stars. Constellations/star patterns may vary culturally and historically but they occur across all of them. There may be a way to better describe our place in the cosmos but our innate ability to organize randomness cannot be suppressed.

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CounterWeight
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Re: unlearning the constellations new [Re: Tony Flanders]
      #5510677 - 11/08/12 10:12 PM

Quote:

i am certainly intrigued, even fascinated, by the sentiment repeated here that my proposal to look at the sky with fresh, wide eyes is equivalent to trashing the past, burning books, forbidding ideas, purging texts, policing speech or denigrating culture.

as i said, i decline the opportunity to debate those points further. but i appreciate the demonstration of the grip that tradition holds on the mind.





I think either you missed my point or I muddled it. The past cannot be debated - and not my intention.

My point is what do you intend to retain, if anything at all. This with a mind to not repeating it or simply re-organizing into something purely self suiting.

As I tried to link to... a 3D representaion has ALREADY BEEN DONE. Please convince me you are not re-inventing the wheel.

What are you bringing to the party that others have not already contributed?

It's as though in trying to contribute or even understand... one gets 'dissed' as bound by orthodoxy.

Quote:

the next step, perhaps the most difficult step, is selecting out of the visible sky the features that can orient the observer and mark out the galactic landscape.





who's galactic landscape? What we do know of and have data for... already done, or am I missing something here? I and at least one other responder linked you to it. This for folks that have no access to the web or star chats/atlas? Living in the city and can't see milky way? And it's to be somehow intuitive? All inclusive?

Quote:


what would a list of "bright" stars, however defined, be used for? at least:

* for orientation to the night sky (e.g., season, sidereal time, direction, latitude)
* for orientation to galactic features (e.g., the galactic center, the local arm)
* as a descriptive sample: what kind of star is a typical bright star?
* as a representative sample: what does the population of stars look like?
* as an enumerative sample: what is a visible example of every kind of star?
* as a local sample: which stars are visible local stars (within X parsecs)?






At the risk of repeating myself, this too has been done... at least for anyone willing to look for the information. And that takes surprisingly little effort.

Not re-inventing a perfectly useful wheel - fine.


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derangedhermit
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Re: unlearning the constellations new [Re: drollere]
      #5510715 - 11/08/12 10:31 PM

Quote:

i am certainly intrigued, even fascinated, by the sentiment repeated here that my proposal to look at the sky with fresh, wide eyes is equivalent to trashing the past, burning books, forbidding ideas, purging texts, policing speech or denigrating culture.

as i said, i decline the opportunity to debate those points further. but i appreciate the demonstration of the grip that tradition holds on the mind.




Is there an "ignore this user" function in the forum software? I can't find it.


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mark8888
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Re: unlearning the constellations new [Re: Tony Flanders]
      #5511015 - 11/09/12 03:50 AM

Quote:


Nobody has objected to your proposal to view the sky with fresh eyes, and many of us have enthusiastically embraced it. But you seem to be the only one here who finds that the old system obstructs the new one. Most of us have no trouble viewing reality simultaneously from multiple perspectives.





I agree with this. It's an interesting topic and a great thread, and I certainly agree that it's important to see the sky intuitively, with our place apparent in the galactic landscape, and any effort to make that easier is a good and valuable thing. But it's as if the poster is saying, humans are incapable of "getting" that two birds are flying at different altitudes if we also note that they appear near each other from our perspective, and if that information proves useful in some way. Of course, we can do both. Most people with even a passing interest in astronomy already understand this and see the sky both ways.


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bumm
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Re: unlearning the constellations new [Re: Dennis_S253]
      #5511847 - 11/09/12 03:18 PM

This has been an intriguing thread. I've contributed a couple of posts, but I'm getting a little lost. I may be missing something, but I get the impression that the OP figures that the constellations somehow detract from gaining a broader understanding of the universe. Surely, if someone figures that the constellations are somehow magically arranged as stellar art, or that the visible stars are all at the same distance, this may be the case, but I've never met anyone with a view of the universe this misleading or primitive.
To the vast majority of starhoppers, the constellations serve as an extremely effective and convenient "coordinate system" for finding things in the sky. One could use RA & dec, but the constellations are essentially engraved on the sky, requiring no other equipment to measure and read.
Does this system somehow stand in the way of gaining a broader understanding? Of course not. If anything, having to look at the sky, with it's different star densities in different areas, the proximity or "avoidance" of certain objects to the Milky Way, the visual structure in the Milky Way, and any number of other variations leads to a greater understanding of the solar system, the galaxy, and the universe for anyone who's curious enough to want to know.
In my personal opinion, one would learn much less about the universe by only finding objects by their RA & dec coordinates, or worse yet, letting a GOTO scope find everything without paying any attention to where the scope is pointed.
And no, I'm not arguing against GOTO...
Marty


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Tom Polakis
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Re: unlearning the constellations new [Re: bumm]
      #5511897 - 11/09/12 03:51 PM

Quote:

This has been an intriguing thread. I've contributed a couple of posts, but I'm getting a little lost. I may be missing something, but I get the impression that the OP figures that the constellations somehow detract from gaining a broader understanding of the universe.




No, it doesn't sound like you're lost at all. That's a good summary of what the OP is insisting is the case.


Quote:

To the vast majority of starhoppers, the constellations serve as an extremely effective and convenient "coordinate system" for finding things in the sky. One could use RA & dec, but the constellations are essentially engraved on the sky, requiring no other equipment to measure and read.




Exactly. With all of their flaws, I find that constellations draw associations similar to states in the U.S. Just as I associate Florida with swamps, New England with rolling hills, and Colorado with jagged peaks, the constellations serve the same purpose. They aid rather than hinder my 3-D perspective of the sky. Ophiuchus is that constellation with the globular clusters due to their position in the galaxy's halo. The Supergalactic Plane cuts through Virgo and Ursa Major, hence all those relatively nearby galaxies.

Knowledge of the constellations and a perspective on the structure of the universe are in no way mutually exclusive. If I didn't embrace both as enjoyable pursuits, I'd be inclined to get another hobby.


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Crossen
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Re: unlearning the constellations new [Re: bumm]
      #5511980 - 11/09/12 05:04 PM

Quote:

If anything, having to look at the sky, with it's different star densities in different areas, the proximity or "avoidance" of certain objects to the Milky Way, the visual structure in the Milky Way, and any number of other variations leads to a greater understanding of the solar system, the galaxy, and the universe for anyone who's curious enough to want to know.




When I read this, it reminded me of W. W. Morgan's story about how he discovered the Perseus Spiral Arm:

"I used to go to Cleveland for a week or so every few months [to meet with J. J. Nassau to work on the identification of Galactic OB stars], for a number of years. Nassau and I did all the classifying. . . . We had a belt I believe 10 degrees wide, as far south as we could get around the sky, and this [provided] the basic catalogue that we used here [at Yerkes Observatory] for taking slit spectrographs of as many of these stars as possible."

"Anyway, in the fall of 1951 I was walking between the observatory and home, which is only 100 yards away. I was looking up at the northern sky, just looking up in the region of the Double Cluster, and it suddenly occurred to me that the Double Cluster in Perseus and then a number of stars in Cassiopeia and even Cepheus--that along there I was getting distance moduli of between 11 and 12. Well, 11.5 is just 2 kiloparsecs, and so I couldn't wait to get over here and really plot them up. It looked like a concentration. . . . . But the hardest thing is to know what's going on if you're in the middle of something. So when I plotted out the Perseus arm, I then plotted out the other stars, and it turned out through the Sun there was this narrow lane parallel to the other one. So that's the way it happened. It was a burst of realization. It was not a question of a reasoned process of steps." (Page 92 of Owen Gingerich's "The Great Copernicus Chase and Other Adventures in Astronomical History.")

Obviously Morgan's knowledge of the constellations helped him visualize what his astrophysical data meant topographically. It also demonstrates how we ourselves can use the constellations in learning Local Spiral Structure. Moreover, many of the constellations are NOT entirely mere chance alignments of stars: Orion looks the way it does in part because almost all its bright stars are members of the Orion Association. Most of the bright stars in Scorpius, Lupus, Centaurus, and Crux are members of the Scorpio-Centaurus Association. The Big Dipper (anciently known as "The Wagon") stands out because five of its seven stars are the core of the Ursa Major Moving Group. Alpha and Beta Aquarii are members of a decayed association. The face of Taurus and the Hair of Berenice are open clusters. Naturally most of the constellations are indeed chance alignments of stars. But enough of them are not that learning the constellations is a very good first step in getting "Galactic depth perspective."

Craig Crossen


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Kfrank
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Re: unlearning the constellations new [Re: derangedhermit]
      #5513325 - 11/10/12 03:29 PM

Quote:

Quote:

i am certainly intrigued, even fascinated, by the sentiment repeated here that my proposal to look at the sky with fresh, wide eyes is equivalent to trashing the past, burning books, forbidding ideas, purging texts, policing speech or denigrating culture.

as i said, i decline the opportunity to debate those points further. but i appreciate the demonstration of the grip that tradition holds on the mind.




Is there an "ignore this user" function in the forum software? I can't find it.




I am intrigued and even fascinated by the fact that the OP continues to dismiss those who refuse to jump on his bandwagon as hide bound traditionalists.

Putting forth a controversial proposal, refusing to engage in debate with regard to it and dismissing those who disagree as either simpletons who just don't understand or bound by tradition hardly seems to be the way to get one's point across.

Bruce, I too decline the opportunity to debate this further.


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Mxplx2
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Re: unlearning the constellations new [Re: Kfrank]
      #5514051 - 11/11/12 07:37 AM

DANGER!!!

EGOS AT WORK.

ENTER WITH CAUTION!


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drollere
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Re: unlearning the constellations new [Re: Mxplx2]
      #5514432 - 11/11/12 12:50 PM

a simple place to start the list of anchor or critical stars, the bright stars that orient the observer to the galactic landscape, is with local bright stars -- "companion" stars.

this list depends in part on the magnitude cutoff, in part on the distance cutoff, and in part on an inclusion cutoff ... but i've chosen a magnitude of about 2.0, a distance of 10 about parsecs and an inclusion of 10 stars. this yields the selection below:



stars in red are just outside 10 parsecs, but arcturus is useful to mark the north "window" of the galactic pole.

the selection provides two stars in the winter galaxy, and two stars in the summer galaxy, both very bright and distinctive, and a single bright star near the galactic north and south poles. the diagram, which represents the true distances in relation to equatorial north and the points of solstice, shows a nice distribution.

the 10 parsec sphere is the basis for absolute magnitude, so it is useful to describe the magnitude system, its definition as a logarithmic scale, and the fact that a log scale defines our visual sensitivity and perception of brightness.

it's also useful to characterize the close solar neighborhood, for example as an enumeration of *all* stars within that distance. according to the hipparcos-yale-gliese database (documented and available HERE), the enumeration looks like this (spectral type shown as size and color of icon):



remarkably there are 325 stars in HYG within 10 parsecs, half of them at magnitude 11 or fainter, and over 80% of them too faint to see with the naked eye. most of our "neighbor" stars are invisible to binocular assisted eyes and not part of any constellation asterism.

the reason is that most are K and M type stars (small red icons), cooler and less massive than the sun and also much fainter. (far from being an "average" star, the sun is actually above average, and above median.) in fact the hipparcos and gliese surveys suffer the same "brightness bias" that afflicts every branch of astronomy, because the true number of stellar mass objects within 10 parsecs is higher by an unknown but significant amount.

the james webb telescope, optimized for large aperture infrared astronomy, may indicate by how much. in the meantime, a 10 parsec radius defines a sphere of about 4200 cubic parsecs. given only the stars we see, this implies an average distance between 325 stars of about 3 parsecs.


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drollere
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Re: unlearning the constellations new [Re: CounterWeight]
      #5514487 - 11/11/12 01:29 PM

Quote:

As I tried to link to... a 3D representaion has ALREADY BEEN DONE. Please convince me you are not re-inventing the wheel. What are you bringing to the party that others have not already contributed?



i've been as plain as i know how to be: the goal is to identify naked eye markers and asterisms, easily identified in the night sky and easily remembered as indicators of basic facts, facts that represent a basic orientation to our place in the galactic landscape and identify features that are significant examples of galactic process.

i believe i have never challenged the utility of the IAU constellations as tracts in a "two dimensional" celestial area, and i have never made the claim that the past needs to be discarded as useless.

yes, i have said that the tracts are inherently arbitrary, and that the past is fine for those who find it interesting, and specifically that cultural history is irrelevant to organizing and remembering our current understanding of the galaxy.

and yes, i have made the claim that the currently available astronomical literature offers very little support for anyone interested to "see" the galactic landscape apparent to us, and i have made the claim that it is useful to "forget" or "unlearn" the constellations in order to let the eyes (not the learned constellation concepts) do the looking in order to find and piece together the useful asterisms and markers. (see the post above about how the constellations actually appear to the naked eye, if viewed without prejudice as to "what i should see".)

what part of that is unclear or poorly expressed?

Quote:

who's galactic landscape? What we do know of and have data for... already done, or am I missing something here? I and at least one other responder linked you to it. This for folks that have no access to the web or star chats/atlas? Living in the city and can't see milky way? And it's to be somehow intuitive? All inclusive?



you're throwing a lot of issues at me there. but the nub is this: go to "atlas of the universe", or pick up henbest & couper's "guide to the galaxy", and you have a trove of catalog and graphic information about the galaxy, as imaged from a point far from the earth.

my question to you: what does all that look like as imaged from the earth? if you go out to the sky tonight, in which direction are the significant features?

it's an entirely different cognitive and spatial problem to orient yourself to a map of new york, to orient yourself while standing in times square, and to connect the two as an intuitive understanding of direction and distance. yes, there are lots of maps or three dimensional visualizations of the galaxy. but none of that is helpful to the naked eye or binocular astronomer as an answer to where we are located, what we can see from where we are located, and how what we can see relates to the whole.

that is explicitly stated in the OP: i said i was looking at the sky, and realized that the traditional constellations did not clearly or memorably indicate the major galactic features visible to me.

a simple example is that there is no asterism commonly used by astronomers to identify the center of the galaxy in the same way that there is an asterism (the dipper) commonly used by astronomers to find the pole star. or to identify the local arm. or to identify the galactic pole. and so on ...

in other words, there is no astronomical "lore" delving the galactic landscape as viewed from earth that even begins to rival (much less challenge) the lore about constellations -- their antiquity, their mythology, and their shopping basket contents of interesting and conceptually unrelated things to look at within an arbitrary area of sky.


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bumm
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Re: unlearning the constellations new [Re: drollere]
      #5514513 - 11/11/12 01:50 PM

Drollere was saying

a simple place to start the list of anchor or critical stars, the bright stars that orient the observer to the galactic landscape, is with local bright stars -- "companion" stars.

But how do we find these more suitable anchor stars? By their position in the constellations?
Marty


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drollere
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Re: unlearning the constellations new [Re: drollere]
      #5514573 - 11/11/12 02:26 PM

we have the companion stars, we know that rigil kent, sirius, procyon, altair, vega, fomalhaut and (approximately) arcturus are all within 10 parsecs. and these bright stars define an area of many unseen companion stars, but most too numerous and faint to identify.

the first asterism is the "summer triangle" of altair, vega and deneb. this is my first galactic asterism.

the elegance of this asterism is that it actually defines a long rectangle receeding into the distance, like a long, straight, road. to anchor the point, i can draw it with a dotted line down the middle:

we have the companion stars, we know that rigil kent, sirius, procyon, altair, vega, fomalhaut and (approximately) arcturus are all within 10 parsecs. and these bright stars define an area of many unseen companion stars, but most too numerous and faint to identify.

the first asterism is the "summer triangle" of altair, vega and deneb. this is my first galactic asterism.

the insight provided by this asterism is that it actually defines a long rectangle receding into the distance, like a long, straight, road. to anchor the point, i can draw it with a dotted line down the middle:



vega and altair, as companion stars, are both quite close to us (about 6.5 parsecs) and to each other (about 4.5 parsecs). in contrast, deneb is very far away -- so far away that its distance is uncertain. i've put it at 990 parsecs, but 1000 parsecs is easy to remember and 100 times farther than our companion stars, if we just say they are 10 parsecs distant and 5 parsecs apart.

now, simple perspective means deneb is the vanishing point, so that the width of the two sides of the triangle common to deneb defines the visual distance between altair and vega at greater distances than 10 parsecs. and this is measured as the distance from deneb to the baseline between vega and altair -- geometrically, the triangle height. located at half height from deneb, the baseline is twice the baseline distance of 10 parsecs, or 20 parsecs away; at 1/4 height, it is 40 parsecs; at 1/10 height, it is 100 parsecs, and so on. the triangle becomes a simple visual guide to judging the effects of distance on apparent size.

the three crossarm stars in cygnus, indicated by their bayer letters, can be distance located along this "road". the location of the 4.5 parsec baseline is shown for delta and epsilon, which are roughly 3 times and 8 times farther from us. the baseline for gamma is not shown because it is half the distance between us and deneb, or 470 parsecs, so its perspective baseline would be located 10/500 the triangle height from deneb.

it's possible to lard this framework with a lot more spatial information, for example as the apparent separation of the 5 parsec interval at different distances, or the apparent magnitude of vega and altair at those distances:



so this asterism -- the summer triangle with the three crossarm stars, forms a visually obvious and intuitive illustration of distance and the effects of distance on visual size and magnitude.

the fact that vega and altair at the distance of del Cyg are both near the naked eye threshold, and at gam Cyg are far below that threshold, gives some context to what distance means to "solar type" magnitudes (both are type A stars, roughly 30 times brighter than the sun). using the inverse square law, we know that vega and altair at twice their distance (near epsilon) will appear 1/4 as bright, and at the distance of deneb will appear 1/10,000th as bright.

the fact that at deneb's distance they would appear separated by only 16 arcminutes puts context around distance and apparent size.

there is also the fact that the vega altair baseline cuts across the visible galaxy at about galactic longitude 60, which has been found by radio astronomy to be the "tangent line" or outer border of the galactic arm nearest to us toward the galactic nucleus (the carina sagittarius arm, which as we now see extends far beyond sagittarius). so this triangle actually forms a "window" through which we see the interval between this inner arm and our local arm -- we are looking between the two arms, as if looking up a long canyon or valley ... or the way a surfer, riding a large wave, looks back at the curl closing behind him.

it also reveals a significant problem: accuracy is a form of clutter. not a lot is lost by saying deneb is 1000 parsecs rather than 990 parsecs distant. or that vega and altair are separated by 5 parsecs rather than 4.5 parsecs, or that epsilon is 20 rather than 22 parsecs and delta 50 rather than 52 parsecs and gamma 500 rather than 470 parsecs away. the simpler numbers are easier to remember, and easier to manipulate as ratios of triangle height (1/2, 1/5, 1/50).

explaining the galactic landscape to a novice or a young person, simplification is essential. it's only by looking at several galactic asterisms that we can decide how much simplification is necessary as a general principle.


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CounterWeight
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Re: unlearning the constellations new [Re: drollere]
      #5515584 - 11/12/12 07:57 AM

Not trying to disagree with anything, but am curious if you have read that book "A Skywatchers Year" by Jeff Kanipe? I was looking through for candidate stars and reference... just curious.

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drollere
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Re: unlearning the constellations new [Re: bumm]
      #5517714 - 11/13/12 11:23 AM

Quote:

But how do we find these more suitable anchor stars? By their position in the constellations?



all i can say is, try the "naive looking" i described in a post above.

i'm pretty sure that you do not locate the constellation canis major in order to find sirius, or piece together the faint stars of lyra to identify vega. you don't first find the constellation of canis minor in order to find procyon ... because procyon is all there is.

bright stars form a whole sky pattern, and that is how you orient to fainter patterns.

indeed, if you study the history of astronomy as crossen advocates, you'll find that bright stars (such as sirius) and a few bright asterisms (dipper, orion, pleiades) are at the root of sky lore. constellations as a general feature of astronomy appear with the rise of astrology, and with the need to identify fainter stars by their position within a standardized figure. this method is fully developed in ptolemy, and persists until william herschel.


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drollere
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Re: unlearning the constellations new [Re: drollere]
      #5517855 - 11/13/12 12:40 PM

looking outward from the galaxy center, the galaxy band presents a striking contrast from the summer triangle:

1. there are many more bright stars
2. the galaxy band appears less bright, or is not visible

the bright stars form an enormous and complex pattern, as illustrated below.



the important goals are, again, to anchor concepts of distance and scale, and to identify important features. i played around with different groupings, starting with the large hexagon formed by sirius, procyon, pollux, capella, aldebaran and rigel. but i ended up with something more modest: three triangles. i've also added star nomenclature, distances, spectral types and molecular cloud imagery.



1. the distance from pollux to capella is 34, the same as the distance from vega to altair. it can be used in the same way to evaluate apparent size in relation to distance.

2. the triangle of alhena, capella and aldebaran is centered on alnath, and distances form a 10, 20, 30 and 40 parsec sequence, in alpha beta gamma order. the triangle encloses the auriga gap, and the gem OB1 molecular complex at 2000 parsecs distance.

3. a line extended from capella through alhena defines the north and east edge of the molecular concentrations, which are bounded on the south and west by a line from betelgeuse to sirius: the galactic equator is midway between them. the north line passes near the old and young clusters M46 and M47, at about 1700 and 500 parsecs distance, which therefore are situated above (direction of galactic north) the midplane of the galaxy disk.

4. the triangle of sirius, betelgeuse and rigel encloses the molecular clouds associated with barnard's loop and the orion nebula, a star forming region at around 400 parsecs distance.

5. the stars of the orion asterism are all closer to us than the nebula, by almost half. rigel, saiph and the outer belt stars from a trapezoid at about 250 parsecs; betelgeuse is at roughly half that (130 pc), and bellatrix at roughly half that again (75 pc).

6. the most distant bright star in this area is eta canis majoris, at 980 pc, almost exactly the same distance as deneb. as a visual cue of depth, the triangle of eta with wezen and adhara is, at its distance of ~1000 pc, the same size as the triangle of sirius, betelgeuse and rigel, visualized at rigel's distance of 250 pc. both triangles lie on the inner side of the local arm, and visually describe its recession away from us.

7. stars toward the orion asterism are relatively young and many are intrinsically bright. in fact, they form an orderly sequence in which the absolute magnitude increases with distance: this is why all stars in the asterism are comparably bright.



the sirius triangle region is an excellent illustration of molecular clouds, H-II regions and massive star formation, absolute magnitude and distance, and a good range of "early" or recently formed spectral types.

despite the numerous bright stars, this whole area is relatively barren of distant structures. a "perseus arm" is hypothesized to lie at a distance of 2000 to 3000 parsecs, but the arm is not clearly defined and in fact a considerable extent of the galaxy outward from the sun's location appears turbulent and disrupted. the conventional image of the galaxy is misleading when it shows dense, clearly defined spiral arms in this direction.


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drollere
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Re: unlearning the constellations new [Re: CounterWeight]
      #5517869 - 11/13/12 12:47 PM

Quote:

am curious if you have read that book "A Skywatchers Year" by Jeff Kanipe? I was looking through for candidate stars and reference... just curious.



don't know it, but i will look for it. thanks!

i am leaving today to boot up a house in mariposa, california, the possible site of future observing. i'll return to this topic later this week.


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CounterWeight
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Re: unlearning the constellations new [Re: drollere]
      #5519588 - 11/14/12 02:09 PM

Bruce,

Nice work there!

I think it's still available("A Skywatchers Year" by Jeff Kanipe), but a bit pricy, i think my version is from 1999 - maybe better to find at a used book store if one in your area.

it's a very diferent treatment of the topic, though i think in ways very much along the lines of what you might be after, I am just saying 'along the lines'. it does include some very widefield orientation diagrams and amplifying info about galaxy disk and things like where a meteor shower will come from... it's really an educational read in ways others aren't, part of it by virtue of a weekly indexing.

One useful device I have is the Daivid Levy 16" planisphere. This planisphere includes outline of Milky Way (with center mark near Saggit/Scorp), Ecliptic path of planets, and interestingly the triangle formed by Altair, Deneb, Vega that contains the 4 star structure of Cygnus. Being large it is far easier to use at night than my small ones.

It's impressive how much it can convery in a very short amount of time. yet by virtue of that can also come up quite short without a lot of amplifying information, depending.

I'm not trying to be contrarywise to what you are after at all. Just the curse of being a bookworm is I have many books and more than a few planishpheres.

That's why I am putting all the Q's out to about the idea. Rare ocassions where my daughter has friends over and it's clear and I'm doing visual, I love to hand them the planisphere and show it's usefulness as an orientation tool, then if attention span still there show the 'books'. But for all that, still extremely difficult to convey as you mention our 'neighborhood' and then even more the relationship of this neighborhood to the rest. Of all questions the 'how far away' is most asked. If I'm understanding your intentions there is definately room for something that could easily and quickly convey this, and I suspect it would be quite popular


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bumm
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Re: unlearning the constellations new [Re: drollere]
      #5519901 - 11/14/12 06:19 PM

Quote:

Quote:

But how do we find these more suitable anchor stars? By their position in the constellations?



all i can say is, try the "naive looking" i described in a post above.

i'm pretty sure that you do not locate the constellation canis major in order to find sirius, or piece together the faint stars of lyra to identify vega. you don't first find the constellation of canis minor in order to find procyon ... because procyon is all there is.

bright stars form a whole sky pattern, and that is how you orient to fainter patterns.

indeed, if you study the history of astronomy as crossen advocates, you'll find that bright stars (such as sirius) and a few bright asterisms (dipper, orion, pleiades) are at the root of sky lore. constellations as a general feature of astronomy appear with the rise of astrology, and with the need to identify fainter stars by their position within a standardized figure. this method is fully developed in ptolemy, and persists until william herschel.




Well, I can't speak for everyone, but I pretty much see the sky as a whole. Often, a bright star in a known location IS easier to pick out than the surrounding constellation. However, I generally confirm the identity of a star by looking at it's position among it's fellows... i.e. the constellations. This is true especially if I happen to be out at an unusual time. The Summer triangle is very conspicuous, and it's easy to identify the individual stars. However, it's not worth much for starhopping. I see Canis Minor as two stars... the brighter one is Procyon. By itself, theres nothing distinctive about Procyon. I'd have to confirm it's identity by the way it relates to Gemini. Sirius isn't much of a problem that way... it's distinctly BRIGHT. However, how many of us don't notice that it's following Orion?
Planispheres have been brought up in this discussion. I happen to collect old planispheres and love the things. (as some here might guess. ) However, when I look at a military type planisphere showing only navigational stars with no constellations, I can eventually get oriented, but for my needs as an amateur astronomer, something is lost.
Not meaning to pick nits... You've put forth a considerable effort here. But still, I'm having trouble seeing the advantage of ignoring the constellations in favor of certain well picked individual stars.
Marty


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bryguy27007
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Re: unlearning the constellations new [Re: Astrodj]
      #5533174 - 11/22/12 12:03 AM

Quote:

Bruce,

I imagine a planetarium program that could be told to show the naked eye sky from any location in or near the galaxy. It would be like having a virtual spaceship. One would quickly get lost if the program were so sophisticated as to able to put the reference point into light years per second motion.

I wouldn't mind heading out toward the Cone Nebula and tooling around for a while to see what the area looks like from other angles.

My interest in forming a mental picture of the actual 3D location of common celestial objects within our galaxy took
flight when I learned that the vast majority of what is visible to the naked eye is contained within a relatively small bubble of space with a radius of roughly 1500 parsecs, with us being in the center of the bubble.

Only 7,000 or so of the nearest AND brightest stars are visble to the unaided eye, mostly within that bubble, out of 2 or 3 hundred billion stars in the galaxy. Over half of either total are red dwarfs with only a scant few visible without optical aid, even the relatively near ones.

Looking toward the learned constellation of Saggitarius without optical aid, we can see (with a few exceptions) only about an eighth of the distance to the center of our galaxy. Same story along the galactic plane in the opposite direction towards the outer edge. Then there is the other entire half of the galaxy left to consider.

It's a lot to map, and I have only a very rudimentary knowledge of where the objects I can see actually are on that map so far, but I'm learning.

I too spend most of my time observing the "objects" in a telescope, because I enjoy it so much. But, I do make an effort to mentally place said object within our galaxy where it belongs, as best I can. Knowing what else is also in the locale of that object however, is another question that goes largely unanswered for me most of the time.




You might find this video extremely interesting.
http://www.youtube.com/watch?v=8agz9FcDcPk


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mark8888
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Re: unlearning the constellations new [Re: bryguy27007]
      #5533664 - 11/22/12 10:12 AM Attachment (14 downloads)

http://workshop.chromeexperiments.com/stars/

Helloooooooooo easy to use 3D map. This is great.
The trick is to zoom out a little past the oort cloud and then get a sense of the layout and the grid pattern by moving the mouse and shifting your perspective. Then zooming out slightly more and doing the same. Takes a little while to get the hang of it but the effort is rewarded. Awesome!
Works in chrome and possibly firefox, but apparently not explorer.
No program to download or instruction book to read. It works right in the browser.
By the way, of course I didnt make this! Others have been linking to it.
I'll attach a screen shot of this program in action.


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dUbeni
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Re: unlearning the constellations new [Re: Dennis_S253]
      #5541310 - 11/26/12 11:27 PM

Thank you OP, and all those that contributed to this "Great Post". A true insight into our home in the Milky-Way galaxy.

Quote:

... The thing that makes me wonder is "how" did the old ones get all there idea's? They didn't have light pollution, I don't think. And as some have said, from a dark sky there are so many stars that it is hard to pick out constellations. Orion is just a bunch of stars. Bright stars that make a pattern that is one of the most reconized. I'm sure that (I know) all them stars are not all associated with each other.




They didn't have light pollution but they had the moon, and in a moonlit night, even with great skies, only some asterism standout. To them stars were fixed on a sphere,there were no distances, and maybe they just named the asterisms after things that were significant to there life's, like the hunter, the water bearer, the bull, the ram, etc.
Until recently the only asterism I knew was a trapeze with 3 stars on a diagonal that I called "the 3 Mary's", now I know it's part of the Orion constellation. When I was 12 years old, and men went to the moon, I started wondering about the universe and how it would be like to see it from the outside, and how far out would I have to go, knowing it was impossible due to its infinite size.

As a beginner (2007), I obviously started with the constellations, as a road map of the sky in medium polluted skies, it works well. Anyway I feel the need know more about the relative position of the solar system plane and the galactic plane and how objects fill the space around us.
I support the idea of OP, of creating new maps of the sky with more 3D and galactic information.
It is fun to look at distribution of open clusters along the galactic plane vs the globular clusters on Hayden Digital Universe. Although I new that, its hard to see it on the charts.
I'm having a lot fun with the Hayden Digital Universe, great perspectives from within and the outside Milky-way (just starting to use it).

Clear skies
Bernardo


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Starman1
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Re: unlearning the constellations new [Re: dUbeni]
      #5542370 - 11/27/12 03:52 PM

Periodically, the "veil lifts" and we see reality for what it is:
One night at Mauna Kea, observing with friends, the Milky Way rose.
Now, at that latitude, the Milky Way doesn't rise tipped to the horizon--it rises parallel to the horizon.
The bulge of the Milky Way made it look, and just for a while, as if I was IN a spiral galaxy, fairly near the core, and seeing the huge bulge of that core covering a good swath of sky in front of me.
At that moment, I actually 'felt" the size of the galaxy and our place in it. And, looking around at other areas of the sky, got a sense of three-dimensionality to the whole sky and all the stars seen.
These moments of personal serendipity are just too rare.


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payner
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Re: unlearning the constellations new [Re: Starman1]
      #5542498 - 11/27/12 05:13 PM

Enjoyed reading your experienced perspective, Don. You drew an incredible picture with words.

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NGC7088
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Re: unlearning the constellations new [Re: payner]
      #5600556 - 01/01/13 11:52 PM

WOW!
What an amazing topic!
I started my "feel" for the galaxy by reading Crossen's Binocular Astronomy (first edition) way back when. To me he's the father of this topic and I feel honored and privileged to find he's still around and now I'm sharing not only an era but also web space with him. Hello Mr. Crossen, I don't even feel worthy to be here while you are!
To Drollere:
Write your book and all of us will read it and enjoy it and learn from it and be a bit wiser. But I guarantee you one thing. All your Group names and locations, associations and directions for "this and that" feature here and there will always contain reference to the ol' constellations names. Exactly like you've already done in each of your posts so far so it will be in your book. Because they are here to stay. Good luck!


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