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My evolving interest in double stars....(long)

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#1 Michael Rapp

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Posted 08 February 2014 - 12:49 PM

I am quite surprised at how much I am enjoying double stars.

For fifteen years, other than an occasional look at Alberio or the Double Double, I never looked at them. After all, as my thinking was back then, real amateur astronomers were deep sky observers and double stars were a holdover from the late 19th and early 20th century when amateurs didn't have large scopes suitable for "real" amateur astronomy.

I started trying to observe doubles in a fit of frustration. I have access to a wonderful dark site, but it is 120 miles away from my house and that two-hour drive home was killing me. Desperately wanting to do astronomy, I started trying to find some doubles from my driveway at home. At best, I thought it would be a poor substitute for deep sky observing, but at least I would be doing observing.

It was also at this time that I had purchased one of OPT's $80 C102s that were on sale. I bought it on a whim without any consideration to using it for double stars. However, when I started to observe doubles last summer, I chose that scope, after all I had always heard that refractors were excellent for doubles.

Even before I really had started my double star experiment, I noticed how pleasing stars looked through the refractor: nice tight pinpricks. Indeed, star tests showed the C102s optics, while achromatic, were better than my 8" reflector. (Stars at best focus always look fuzzy, but the optics haven't been recoated in twenty years.)

I was lucky to start observing doubles -- mosquitoes not withstanding -- in the summer as here in Texas we get these high pressure systems that just park themselves over the state at the air just does not move. I remember looking at Cor Caroli and Ras Algethi. I remember thinking, "these are quite pretty." I recall finding the view of Cor Caroli's brightness difference striking and the color contrast of Ras Algethi very pleasing.

I also enjoyed the delicate airy disc and diffraction ring of the star image. With the exquisite seeing, to my utter surprise, I found the steady disc and just-barely-quivering first diffraction ring of the stars to be quite aesthetically appealing.

From those early days, I've continued my explorations into double stars. I've given many things a try. I have found that my strongest interest is in colored doubles. I also enjoy bright stars with dim companions (Delta Cygni, for example). Stars with roughly equal magnitudes and identical colors aren't capturing my interest so much. I've noticed that for easily splittable pairs, it has got to have some color contrast for me. For example, Beta Monoceros, while I can appreciate the geometrical arrangement, just doesn't wow me like it does others.

I would like to try measuring double stars this summer (our winter seeing just isn't good enough for this, I believe.) I found a Celestron Microguide on eBay a few months ago and I have Jeremy Perez' plans for making the measuring device.

I stopped using the refractor as near zenith the eyepiece was just too low to the ground and at high magnifications the colors of stars would all turn yellowish. I switched to my 5" Mak which is an exceptionally convenient scope to use. I can pick it up on my LXD-75 and take it from the garage to the driveway in one trip. Its long focal length, 1900 mm, helps, too. (However, I don't find its star images as pleasing as the refractor. The Mak gives a very sharply defined first diffraction ring as if someone drew a circle around each star with a pencil. I find it distracting and much prefer the subtler ring of the refractor, but it isn't enough to make me drop $1600 on a 5" APO yet.)

I'm happy to say I'm enjoying doubles in their own right and not just because I can't do deep sky from my driveway. At the risk of getting overly philosophical, I still deal with the strange thoughts such as "well, this is fun, but if I were viewing galaxies I would be having so much more fun!" or even more ridiculous "why am I wasting time looking for this star? Shouldn't I at least try to get another open cluster under my belt?" Ah, such is the strange baggage I acquired when I started in astronomy when I was in high school and desperately wanted to fit in with those who I considered expert observers.

I simply have to remind myself that one of my most enjoyable observing runs was last October when I spent several hours in Cygnus with just the CDSA in my hand and hopping from double to double, seeing if I could identify and split each one. When the dew hit, in three trips that spanned only ten feet, I had all of my equipment back inside and within twenty minutes I was in bed. It was one of the most restful and refreshing observing sessions I've had in years.

Yes, I think doubles (especially colored ones!) are here to stay for me.

#2 R Botero

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Posted 08 February 2014 - 03:31 PM

You couldn't have put it better Michael! Welcome to the club! ;)
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#3 Ed Wiley

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Posted 08 February 2014 - 04:26 PM

Welcome to the club, Michael. I have a little observatory in the suburban environment. While I love DSOs and observe them at star parties and our dark sky site (90 miles distant), I have learned to develop interests in things that can be studied by walking out the back door. Doubles are perfect for this kind of environment.

Good luck with your observing, I think we will all be interested in your experiences with measuring, the link was interesting.

BTW: I suspect seeing is pretty good in Dickinson, I grew up in the Hill Country.

Good slits,
Ed

#4 labmand

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Posted 08 February 2014 - 04:47 PM

+1 What Raberto said
Michael, your preaching to the choir
I also only recently made this discovery

#5 Perseus_m45

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Posted 09 February 2014 - 08:40 AM

welcome aboard michael..its a love affair for me. heres a great web site for you ..
http://bestdoubles.wordpress.com/
mike hyrczyk

#6 Michael Rapp

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Posted 09 February 2014 - 08:13 PM

Thanks all....yep, I have the bestdoubles site bookmarked. I like how the author is embarking on seeing just how many doubles that 60 mm long focus scope can split!

#7 azure1961p

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Posted 10 February 2014 - 10:56 PM

I highly recommend Argyles book on observing doubles. Its s stand alone book in the marketplace. There are so many apps and programs that make compiling your own list a snap that I'm a little reluctant to recommend a book on star hopping to doubles. Its too easy and enjoyable to craft your own list with objects you specifically have a yen for in terms of brightness and sep etc. . Argyles book however is a great foundation to this. I find its not a once read at all and it does well as a reference too.

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#8 jgrant

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Posted 12 February 2014 - 10:09 PM

Well stated. I discovered double star observing maybe fifteen years ago and don't really know why. Dark skies are available within less than twenty miles, and here in town where I live the light pollution, while sadly increasing, allows seeing the Milky Way. It's just that doubles are fascinating. My favorite scope is a 150 mm Intes Mak/Cas, but I would like the opportunity to use a refractor other than the short focal length 90 mm Stellarvue that I have and enjoy using on big open clusters.

#9 Scott Rose

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Posted 17 February 2014 - 09:35 PM

In November of last year I was trying to set up a new scope for imaging. For whatever reason I got lazy and decided to look at a double star from the hand controller database. Needless to say I spent the next couple of clear nights just looking at doubles. When the weather clears, I plan to keep continue observing doubles with one scope, while the other setup images.

#10 PJ Anway

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Posted 18 February 2014 - 09:12 AM

When the weather clears, I plan to keep continue observing doubles with one scope, while the other setup images.


The best of both worlds. I wish more imagers did this, they might be surprised at how enjoyable observing is again. :grin:

#11 drollere

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Posted 18 February 2014 - 03:48 PM

I highly recommend Argyles book on observing doubles. Its s stand alone book in the marketplace. There are so many apps and programs that make compiling your own list a snap that I'm a little reluctant to recommend a book on star hopping to doubles. Its too easy and enjoyable to craft your own list with objects you specifically have a yen for in terms of brightness and sep etc.

i second pete's comments, on both counts. get argyle; get WDS and compile your own observing list to your own criteria.

it's hard to overstate how fantastic it is to "discover" double stars on your own. i was once looking at star clusters in Puppis, and by wandering from one minor cluster "discovered" LAL 53 floating happily in a milky way field. i still think of that little pair with great affection for the delight and thrill i felt when i encountered it, at random, on my own. BU 442 is another "discovery" made during random wandering. and much of that thrill is looking, for example, at bet MON for the first time without knowing in advance what it is you are supposed to see ...

i don't do photography (yet), but PJ is right that visual observing is a unique and absorbing astronomical endeavor.

it helps to know *how* to develop your observing skill, and also to know a bit about the physical reality of what you are looking at. i looked at double stars for over a year before i had the vaguest idea of, for example, how far apart the stars are on average.

the pages on "double star astronomy" (linked below) are probably overkill, but may whet your appetite and suggest how much there is to know about these critters, and how incredibly productive their study has been to understanding basic things like star formation, stellar evolution, the mass/luminosity relation, the initial mass function, and on and on ...

#12 jturie

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Posted 26 February 2014 - 11:17 AM

Great post. I am gravitating toward double-star observing with my Nexstar 6 and plan to move to a refractor hopefully soon.

DSOs are nice, and I look at them frequently. But...most of them, frankly, look like dull smudges to me. I've looked thru other club members' big dobs (up to 22") and the DSOs look like bigger, brighter dull smudges. Not disparaging DSOs, but since I can't afford to drop 10K on a big Obsession/Teeter, I need to stick to my equipment's strengths.

I have also figured out that double stars make for great outreach. Neophytes are usually underwhelmed when they look at a galaxy, but the kids really think that double stars, especially ones with easily discernible color differences, are cool.

#13 Michael Rapp

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Posted 01 March 2014 - 12:52 PM

It's great fun and very relaxing.

It's the funniest thing.... as I grew up in the latter part of the Dob revolution in which there was a palpable theme of "real astronomers do deep sky....and not just any deep sky, but the deepest deep sky possible! Push the limits of those scopes! NGC objects? Hah! Child's play!" I still -- struggle is a bit too strong of a word, but you get idea -- with such bizarre thoughts such as "How am I enjoying this? Why am I not going for nebulae?" when I observe doubles.

The answer of course is that double star astronomy is astronomy I can do from my driveway. Sure, I love and enjoy DSOs, nebulae and face-on spirals especially, but in order to enjoy them, I must drive two hours from my house, often spending the night, and then drive two hours back. That is a very draining thing to do and there is often a fine line between between being relaxed and drained and just plain drained.

Part of my enjoyment of doubles is a conscious shift-in-focus of my observing. It took some brutally honest courage to accept that where I live, the time and energy I have available, and my weather patterns are not conducive to an observing program that focuses primary on deep sky observing. It is just not practical. To act as if it were otherwise is just a recipe for frustration, misery, resentment, and disappointment.

So I shifted the focus from the objects I was observing to the experience of observing. Instead of the goal being "observe as many eclectic deep sky objects as possible (as if this were some measure of my value in life)" to finding an observational experience that was relatively hassle-free, engaging, relaxing, and fulfilling. I'm not interested in climbing Mount Everest anymore....I just want to have a fun walk around the neighborhood.

#14 R Botero

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Posted 01 March 2014 - 06:14 PM

Amen!

#15 combatdad

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Posted 22 March 2014 - 06:45 PM

Michael,

This is a redo of an earlier post that got lost in the second coming of the old CN, but I still feel compelled to express my total agreement with your enjoyment of double star observing. I fell in love with astronomy when I purchased my first Unitron (Model 114, 60mm, f/15) in late 1958 but turned to double stars about ten years ago as the best use of my Unitron Model 152 (102mm, f/15). I still use my LX90 for occasional DSO sky tours, but for the most part prefer planning an evening of star hopping to previously unobserved double stars. I long ago converted my Unitron from its equatorial mount to a simpler Universal Astronomics Unistar Deluxe mount to make life even less stressful. I have learned so much more about the night sky.

Dave

#16 labmand

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Posted 23 March 2014 - 12:44 PM

Thanks for the revival, so much has been lost, hope this
stays a while this time

#17 drollere

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Posted 24 March 2014 - 12:13 PM

I grew up in the latter part of the Dob revolution in which there was a palpable theme of "real astronomers do deep sky....and not just any deep sky, but the deepest deep sky possible! ... Part of my enjoyment of doubles is a conscious shift-in-focus of my observing. It took some brutally honest courage to accept that where I live, the time and energy I have available, and my weather patterns are not conducive to an observing program that focuses primary on deep sky observing. It is just not practical. To act as if it were otherwise is just a recipe for frustration, misery, resentment, and disappointment.

the twin imperatives of what other people think other people should be doing for "real astronomy", or what is practicable in your location, can be enriched by understanding a bit more about double stars in themselves.

they are first of all neighbor systems. we can see galaxies in other parts of the universe, and star clusters or nebulae in other spiral arms of our galaxy, but the great majority of double stars we observe are within a few hundred parsecs of the sun.

despite their relative closeness, double stars are connected across enormous distances. the median distance among solar type stars is about 50 AU. the widest known comoving system (fomalhaut) is separated by 50,000 AU. double stars, unlike any other deep sky object, display a specific spatial separation as a distinct visual separation. it is rather stunning to strain at the eyepiece to visually separate a pair that is in fact separated by 1000 times the radius of the solar system.

that recognition requires you to either look up or calculate from catalog data the physical parameters of the system you look at, which is a form of research that deep sky astronomers, those "real" astronomers, rarely do. yes, they can tell you that the faint fuzzy is 15 megaparsecs away, but their information is usually an inference from red shift or the tully-fisher relation, which is something quite different from astrometric or spectroscopic parallax.

next, consider history. castor, lovely as it is, is also one of the six systems that herschel relied on to confirm that newton's gravitational attraction was indeed *universal* gravitation, and applied to stars the same as to an apple orchard. you can look at that lovely nearby pair (distance 15.6 parsecs, separation 103 AU, period 445 years, system mass 5.5 solar masses) and see it as a monument to the progress of knowledge, a specific branch of light that humans were able to grasp to pull themselves a little further out of the muck of superstition and myth.

history doesn't stop there. by cataloguing and measuring double stars wherever they were found, the dozen of dozens were found with calculable periods and measurable parallaxes. distance gave brightness, and period gave mass, and by means of those brightness mass relationships the hertzsprung russell mass luminosity diagram was anchored in facts, facts that allowed the reasoning out of nuclear fission and the theory of stellar structure.

even the "waste products" of 19th century interest in double stars, the astrometric measurement of optical doubles, had use: it anchored the recognition of proper motion as galactic motion, and provided the basis for kapteyn's application of dynamics to galactic structure, which was refined by lindblad and oort to confirm the spiral rotation of our galaxy decades before radio astronomy could paint the picture.

the more scientists have looked into double stars, the more they have discovered. eclipsing binaries led to measurements of stellar radii, and clarification of giant and supergiant stars, and the real origin of novae. contact binaries have linked gravitation and black holes, dwarf stars and recurring novae, more pieces in the puzzle of stellar evolution and nucleosynthesis, important bridges in the cosmological narrative. double stars contributed the clues that link us back to the big bang.

the contemporary focus is on star forming regions and the processes by which stars form. and these turn out to be inseparable from the processes by which double stars and star clusters form, and out of them how galaxies form. by the current distribution of their parameters, double stars constrain the dynamics of star formation in ways that allow theories of star formation to be tested and rejected.

on top of all that, double stars, all of them, are unique. unique in origin, components, dynamics, situation, aspect. we live in a turbulent, chaotic universe, and see by the light of stars formed in the turbulent, chaotic collapse and aggregation of fractal masses of gas. the individuality of double stars is really the outcome of that turbulence and unpredictability, but the fact that they all conform to the same dynamics and evolution signifies the foundational importance of gravitation and the second law of thermodynamics in the fabric of our universe.

#18 Michael Rapp

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Posted 25 March 2014 - 11:05 AM

Hi Bruce!

Thanks for your lengthy reflection there. To extend on one of your points, when I was looking at a double a few weeks ago, it hit me that all of the light in the universe is generated from objects such as the ones I was viewing.

Without the stars, there would be no light. It seems a simple, obvious, even plebeian statement, but it hit me that I was considering the fundamental building blocks of the universe...as we see it (pun, sadly, intended). It was a transcendent moment that is so difficult to put into words.

On another one of your points, I've found doubles to be wonderfully interactive. I can try to split them in varying degrees, I can consider their colors, I can interact with the wave nature of light itself through the diffraction rings...I can consider their orbits and should I want to do the math, I can compute them.

I see so many people in my astronomy club bemoaning that they can't get out to the dark sky site on a regular basis, so I'm working on the beginning of a talk. The title is obvious: Double Stars: Not Just Dots in the Sky.

#19 drollere

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Posted 25 March 2014 - 05:13 PM

i also gave a talk on double stars to my local club, and the extended (director's cut) version is available on my web site. it may have some slides you can incorporate.

#20 azure1961p

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Posted 28 March 2014 - 09:16 PM

I grew up in the latter part of the Dob revolution in which there was a palpable theme of "real astronomers do deep sky....and not just any deep sky, but the deepest deep sky possible! ... Part of my enjoyment of doubles is a conscious shift-in-focus of my observing. It took some brutally honest courage to accept that where I live, the time and energy I have available, and my weather patterns are not conducive to an observing program that focuses primary on deep sky observing. It is just not practical. To act as if it were otherwise is just a recipe for frustration, misery, resentment, and disappointment.

the twin imperatives of what other people think other people should be doing for "real astronomy", or what is practicable in your location, can be enriched by understanding a bit more about double stars in themselves.

they are first of all neighbor systems. we can see galaxies in other parts of the universe, and star clusters or nebulae in other spiral arms of our galaxy, but the great majority of double stars we observe are within a few hundred parsecs of the sun.

despite their relative closeness, double stars are connected across enormous distances. the median distance among solar type stars is about 50 AU. the widest known comoving system (fomalhaut) is separated by 50,000 AU. double stars, unlike any other deep sky object, display a specific spatial separation as a distinct visual separation. it is rather stunning to strain at the eyepiece to visually separate a pair that is in fact separated by 1000 times the radius of the solar system.

that recognition requires you to either look up or calculate from catalog data the physical parameters of the system you look at, which is a form of research that deep sky astronomers, those "real" astronomers, rarely do. yes, they can tell you that the faint fuzzy is 15 megaparsecs away, but their information is usually an inference from red shift or the tully-fisher relation, which is something quite different from astrometric or spectroscopic parallax.

next, consider history. castor, lovely as it is, is also one of the six systems that herschel relied on to confirm that newton's gravitational attraction was indeed *universal* gravitation, and applied to stars the same as to an apple orchard. you can look at that lovely nearby pair (distance 15.6 parsecs, separation 103 AU, period 445 years, system mass 5.5 solar masses) and see it as a monument to the progress of knowledge, a specific branch of light that humans were able to grasp to pull themselves a little further out of the muck of superstition and myth.

history doesn't stop there. by cataloguing and measuring double stars wherever they were found, the dozen of dozens were found with calculable periods and measurable parallaxes. distance gave brightness, and period gave mass, and by means of those brightness mass relationships the hertzsprung russell mass luminosity diagram was anchored in facts, facts that allowed the reasoning out of nuclear fission and the theory of stellar structure.

even the "waste products" of 19th century interest in double stars, the astrometric measurement of optical doubles, had use: it anchored the recognition of proper motion as galactic motion, and provided the basis for kapteyn's application of dynamics to galactic structure, which was refined by lindblad and oort to confirm the spiral rotation of our galaxy decades before radio astronomy could paint the picture.

the more scientists have looked into double stars, the more they have discovered. eclipsing binaries led to measurements of stellar radii, and clarification of giant and supergiant stars, and the real origin of novae. contact binaries have linked gravitation and black holes, dwarf stars and recurring novae, more pieces in the puzzle of stellar evolution and nucleosynthesis, important bridges in the cosmological narrative. double stars contributed the clues that link us back to the big bang.

the contemporary focus is on star forming regions and the processes by which stars form. and these turn out to be inseparable from the processes by which double stars and star clusters form, and out of them how galaxies form. by the current distribution of their parameters, double stars constrain the dynamics of star formation in ways that allow theories of star formation to be tested and rejected.

on top of all that, double stars, all of them, are unique. unique in origin, components, dynamics, situation, aspect. we live in a turbulent, chaotic universe, and see by the light of stars formed in the turbulent, chaotic collapse and aggregation of fractal masses of gas. the individuality of double stars is really the outcome of that turbulence and unpredictability, but the fact that they all conform to the same dynamics and evolution signifies the foundational importance of gravitation and the second law of thermodynamics in the fabric of our universe.


Also staggering Bruce is the amazing sub arc second angles for these distant suns...

Using Ganymede at 1.7" as a comparison, nearby fat Betelgeuse is is slightly smaller than 1/30 of its width! Polaris is an astonishing 1/512 the apparent diameter of this object.

Pete






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