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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1075
Loc: Suburban Maryland
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I've experienced this a number of times in the last few years: I buy a new astronomy field guide or download a list of objects to observe, and the author gives the RA and Dec numbers to locate each object, but does not name the constellation it is in! What gives? Are constellations obsolete now? Is it really that cost effective to save a little paper and ink or a few bytes of storage to leave out the constellations?
When I buy a new DSO field guide or search through a DSO list, I want to know the constellation in which each object is located. For me, the constellations are a quick, short-hand method to know not only where an object is located on the celestial sphere, but what would be the best time of year to observe it, what time it would be at the meridian throughout the year, and even if it would be visible at all on a particular night. I can get at least a rough idea of all that information from a quick glance at the name of the constellation. I cannot get the same information from just glancing at the coordinates, and I doubt that many amateurs can. Maybe many newbies don't want to bother with learning the constellations, but are the coordinates any easier to understand when you glance at them beside the object description in a book or on a list, BEFORE you plug them into your goto computer? I don't think so.
I don't have goto or DSCs and I'm not going to get these gizmos for any of my current scopes, so I can't just plug in the numbers and hope I'll be able to see a certain object on a particular night. (Besides, I don't think many binoculars are goto driven.) When I read about an object and I want to see it, the first thing I want to know is the constellation in which it is located. Is that too much to ask? I don't think so.
Clear Skies,
Mike
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Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
Barska XWA 10x50, 8x40
OptiView LPR 10x50
Const View 2.3x40
BV-125C
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SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
QuikFinder, Telrad
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Have GLP and not afraid to use it!
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
I've experienced this a number of times in the last few years: I buy a new astronomy field guide or download a list of objects to observe, and the author gives the RA and Dec numbers to locate each object, but does not name the constellation it is in! What gives? Are constellations obsolete now? Is it really that cost effective to save a little paper and ink or a few bytes of storage to leave out the constellations?
When I buy a new DSO field guide or search through a DSO list, I want to know the constellation in which each object is located. For me, the constellations are a quick, short-hand method to know not only where an object is located on the celestial sphere, but what would be the best time of year to observe it ...
This is an interesting question -- and very relevant to me, since as an editor of Sky & Telescope, I have the choice to include or exclude the constellation in many cases.
Given the three location-defining data(RA, Dec, and constellation), constellation is clearly the least important, because it's the least specific. And frankly, it is neither needed nor terribly useful for knowing what's the best time of year to observe something. For that purpose, RA is far superior.
When in doubt, I can (and often do) figure out when an object culminates using the RA, the date, and a little mental arithmetic. It's simplicity itself. By definition, the Sun is at RA zero on the vernal equinox. Conversely, an object at RA zero culminates at midnight (standard time) on or near the autumnal equinox.
It's now almost a month past the autumnal equinox, so an object at RA zero culminates about 24/12 = 2 hours before midnight standard time, which is 11 p.m. daylight time. This isn't precise, but it's a lot better than I could do based just on the constellation, which might cover several hours of RA.
More generally, I have a feel for when certain ranges of RA are easily viewable in the evening sky. It's easy to acquire this if you think in terms of RA, and well worth acquiring.
RA and Dec are particularly important if you star-hop, because they're what you need to locate your target in a star atlas. Constellation alone won't usually do that. It wouldn't even come close if not for the convenient fact that the NGC objects are arranged in RA order.
Having said all that, the constellation is still a very useful shorthand for combining RA and Dec in a crude kind of way -- and knowing in a jiffy which way you'll need to look in the naked-eye sky. So constellation certainly has its value.
I always omit the constellation from the data tables in Deep-Sky Wonders, which is invariably squeezed for space in the magazine. But this is rarely a problem, because in 19 cases out of 20, Deep-Sky Wonders concentrates on a small piece of sky -- usually just a part of a constellation -- and the name of the constellation is spelled out very clearly in the text.
However, I am planning to publish soon (in the April issue) an article that covers one type of object, with examples scattered all over the sky. And in that case, I'll think much more seriously about including the constellation.
Alas, the real problem isn't the 3-letter constellation abbreviation but the column header. I suppose I can abbreviate it "Const." or even "Con."
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Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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Rick Woods
Postmaster
Reged: 01/27/05
Posts: 5684
Loc: Inner Solar System
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Another vote here for constellation name.
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- Rick
14" LX200GPS
Dyslexics Untie!
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bicparker
Carpal Tunnel
Reged: 02/07/05
Posts: 1706
Loc: Plano, TX
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If I am looking at a list of objects and the constellations are listed with them, then I can, very quickly, ascertain their general position in the sky and mentally group them. Obviously, if the constellation is Eridanus, or Hydra, or some other large meandering constellation, then I would still jump to the RA/Dec references. But, most of the time, it gives me a quick visual and makes me think of the best time frame for observing.
And... in general conversation on the field.. if someone asks where something is, I don't rattle off the RA/Dec to them... I say, "It's here, in Hercules."
Of course, I tell folks that everything is in Hercules. 
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Bic Parker
17.5" f/5 dob
10" f/10 SCT
5" f/8 refractor
80mm f/6 refractor
66mm f/6 refractor
Plus a few others out of the rotation
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desertstars
Please stand by...
Reged: 11/05/03
Posts: 34598
Loc: Tucson, AZ
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The references I have acquired are a mixture of three organizational schemes: coordinates (RA/DEC), constellation, and season. When I pick up a new one, it's an even bet which of the three it will use, and very often it will cross reference at least two out of the three. (Sue French's Celestial Sampler and Tom Trusock's Small Wonders series here on CN are examples.)
I don't see a trend away from using any one way to catagorize objects, in preference to others. Which one a given author decides to use is an exercise in author's prerogative.
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Tom W.
Collinder's Catalog
Jewels in Dark Settings
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stevecoe
"Astronomical Tourist"
Reged: 04/24/04
Posts: 2648
Loc: Arizona, USA
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Tony;
Please listen to your readers and include the constellation information. I know that you can and do quickly and easily make a mental calculation about used the RA and Dec. I use the constellation as that quick method for know what is up right now or later this evening.
The SAC database includes a column of "CON" with the IAU shorthand for each constellation.
www.saguaroastro.org
Thanks for listening;
Steve Coe
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TeleVue 102 refractor on CGEM mount
10 inch f/4.7 Newtonian
Author "Deep Sky Observing" Springer-Verlag
Author "Nebulae and How to Observe Them" Springer
Canon Xt astrocamera with Hutech modification
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Jeremy Perez
Carpal Tunnel
Reged: 08/12/04
Posts: 1930
Loc: Flagstaff, Arizona, USA
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I can definitely sympathize with the pain of having to mash another table column into a layout. Still, I'd gladly toss in another vote for the user-friendliness of listing constellation info for providing a quick sense for where/when something is visible.
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Orion SVP 6LT (6" f/8 Newt) || Orion XT8 (8" f/5.9 Dob) || 15x70 Oberwerk Binoculars || Coronado PST
The Belt Of Venus || Sketch Gallery || Sketching Resources || Astro-Photo Gallery
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astrokido
space wanderer
Reged: 06/09/08
Posts: 666
Loc: Phoenix, AZ
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It's particularly important to know an object's constellation when you're trying to catch it right after astronomical twilight sets in, just before it disappears below the horizon for a month or two.
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- Gill C. - Celestron Cometron CO-100, 10x25, 20x80, Binochair, Nikon D40
The Night Sky Atlas: www.nightskyatlas.com
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BobinKy
Carpal Tunnel
Reged: 04/27/07
Posts: 1683
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Tony...
This is an eye-opener thread for me. Thanks for taking the position you did and defending it with good examples.
I have been a constellation guy for the last three years--I probably always will be a constellation guy.
However, I just went to my software program (SkyTools 3) and created an observing list of the Messiers. The program creates an observing list with the objects listed by rows and descriptor categories in columns (spreadsheet style). This makes it easy to sort the observing list by any of the categories. I never have all of these category columns turned on. But today I did turn all of them on and noticed the following.(1) Sorting by RA is the same as sorting by transit time.
(2) In many of the Messiers, the optimum observing time is the same or close to the transit time.
(3) Millennium Star Atlas and Pocket Sky Atlas come the closest to preserving the RA sort than any of the other atlas options in the program.
(4) Constellations are generally in the ball park when following the RA sort. Conclusion
Following the RA position makes sense if you want to observe the Messiers by transit time or calculated optimum time.
For the evening of October 15, according to the program's calculation of optimum observing times, at the end of twilight tonight I should begin observing the Messiers with the M51 or M3 at location RA 13 hrs 30 mins in the Canes Venatici (CVn) constellation. However, I should wait on the Messiers M63 and M94, also in Canes Venatici, until right before the beginning of twilight in the morning.
A copy of the complete Messier Observing List in Excel spreadsheet format is attached.
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Bob
38°N
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bicparker
Carpal Tunnel
Reged: 02/07/05
Posts: 1706
Loc: Plano, TX
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As a general rule, when making observing lists, I always put everything in RA order. However, seeing the constellation name or abbreviation listed makes it much easier to quickly identify its general location, especially when I am in the dark looking at it with a dim red light.
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Bic Parker
17.5" f/5 dob
10" f/10 SCT
5" f/8 refractor
80mm f/6 refractor
66mm f/6 refractor
Plus a few others out of the rotation
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Tom Polakis
scholastic sledgehammer
Reged: 12/20/04
Posts: 769
Loc: Tempe, Arizona
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Quote:
I suppose I can abbreviate it "Const." or even "Con."
As others have noted, constellation name gives many of us an intuitive feel for an object's location. When I hear "Leo" I immediately think, "Winter mornings, Spring evenings."
If you went with the three-letter "Con" abbreviation, you could similarly use the three-letter abbreviations that already exist for all of the constellations. I'm sure your layout people would appreciate "CVn" in favor of "Canes Venatici."
Tom
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Tom Polakis
Tempe, AZ
Visual observing, DSLR photography, lunar & planetary imaging
http://www.pbase.com/polakis/
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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1075
Loc: Suburban Maryland
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Tony,
Quote:
Given the three location-defining data(RA, Dec, and constellation), constellation is clearly the least important, because it's the least specific. And frankly, it is neither needed nor terribly useful for knowing what's the best time of year to observe something. For that purpose, RA is far superior.
I wouldn't say that the constellation is the least important location-defining datum. Ideally, I want to have all three: RA, Dec, and constellation. Speaking for myself only, a glance at a list of objects that only has the coordinates and not the constellation will not tell me if such and such an object or objects on the list will be visible tonight or approximately at what time tonight. But the constellation next to the object will give me that information. Not always exact information, especially for the constellations that are longer in RA, such as Hydra. But usually good enough to get me in the ballpark with just a glance. The coordinates will not do that for me - at least not with a glance. If I only have the coordinates, I'll have to look up the object in an atlas or plug it into a planetarium or planning program or ... gasp... figure it out in my head. 
Quote:
When in doubt, I can (and often do) figure out when an object culminates using the RA, the date, and a little mental arithmetic. It's simplicity itself. By definition, the Sun is at RA zero on the vernal equinox. Conversely, an object at RA zero culminates at midnight (standard time) on or near the autumnal equinox. It's now almost a month past the autumnal equinox, so an object at RA zero culminates about 24/12 = 2 hours before midnight standard time, which is 11 p.m. daylight time.
When in doubt, I reach for a planisphere, give it a quick twirl, and have the information literally at my fingertips. I doubt that for most people - myself included - the "little mental arithmetic" is "simplicity itself." That's just the way it is. I know people who like doing sums and products in their heads, too. I'd rather use the calculator. (On the other hand, I do know the constellations and brighter stars rather well, so I don't use goto or DSCs. To each their own.)
Quote:
More generally, I have a feel for when certain ranges of RA are easily viewable in the evening sky. It's easy to acquire this if you think in terms of RA, and well worth acquiring.
I do agree with this. I can see the usefulness in learning some basic positions in RA, such as where 0 degrees is (I do know that), and maybe even a rough idea of the RA for each major constellation, and even the beginning and ending RA for long constellations such as Hydra. But if I already know the constellations and have a basic idea of when they culminate, the RA is pretty much redundant. Something for me to think about.  But for now, since I do know the constellations and their spatial relationships and the general time of year when each culminates at midnight, I get by very well as long as I am given the constellation in which an object is located.
Quote:
RA and Dec are particularly important if you star-hop, because they're what you need to locate your target in a star atlas. Constellation alone won't usually do that. It wouldn't even come close if not for the convenient fact that the NGC objects are arranged in RA order.
I generally don't use RA and Dec at all when I star hop. If I'm looking at the object's constellation in an atlas, I can spot the object pretty quickly, as long as the NGC or other designation is printed beside it. If not, I look up the object in the Sky or Sky Tools and print out a finder chart. I don't use RA or Dec to do any of this. Since I've gone through the Messiers and most of the objects that are fairly easy to locate and observe, I might start using RA and Dec more than I have. We'll see. But so far, as long as I've had good finder charts and I already know where the object is in the atlas, I really haven't felt any need for coordinates.
Quote:
Having said all that, the constellation is still a very useful shorthand for combining RA and Dec in a crude kind of way -- and knowing in a jiffy which way you'll need to look in the naked-eye sky. So constellation certainly has its value.
Yes, and I want to know in a jiffy. 
Quote:
I always omit the constellation from the data tables in Deep-Sky Wonders, which is invariably squeezed for space in the magazine. But this is rarely a problem, because in 19 cases out of 20, Deep-Sky Wonders concentrates on a small piece of sky -- usually just a part of a constellation -- and the name of the constellation is spelled out very clearly in the text.
As long as the constellation is clearly obvious from the context, I have no problem if the constellation name is not given in a table. But what's obvious to one might not be obvious to others.
Quote:
However, I am planning to publish soon (in the April issue) an article that covers one type of object, with examples scattered all over the sky. And in that case, I'll think much more seriously about including the constellation.
Good idea! That sure would help me when I read the article.
Quote:
Alas, the real problem isn't the 3-letter constellation abbreviation but the column header. I suppose I can abbreviate it "Const." or even "Con."
"Con" is good. I've seen other authors use that abbreviation and it's what I use in my spreadsheets.
Clear Skies,
Mike
... and please give the folks what they want. 
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Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
Barska XWA 10x50, 8x40
OptiView LPR 10x50
Const View 2.3x40
BV-125C
CG5, 2 drv / CG4, 2 drv, wood legs, ScopeStuff saddle / CG3, 1 drv
SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
QuikFinder, Telrad
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Have GLP and not afraid to use it!
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rookie
scholastic sledgehammer
Reged: 01/14/06
Posts: 881
Loc: St. Petersburg, FL
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Great discussion. I appreciate Tony's explanation. I've been trying to learn the sky for the past 5 years, and I've been organizing my reading, observing, logging, learning star names, and DSO's by constellation. Now there is a file cabinet in my head organized by constellation. I understand the benefits of RA observing for any given night, but it does not sort the information for me. I'm just not there yet.
I get up pretty early and am at work before most people hear their alarm clocks go off. When I observe at night, I'm tired. The extra organization of information makes a difference to me.
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SV
Scope: Celestron CPC8
Binoculars: Garrett GT80~45, Fujinon 16x70, Regals 10x42, Ultima 9x63, Nikon AE 8x40
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
I generally don't use RA and Dec at all when I star hop. If I'm looking at the object's constellation in an atlas, I can spot the object pretty quickly, as long as the NGC or other designation is printed beside it.
That's because you're sticking to warhorses. Sure, if you're looking up Messier objects in the Bright Star Atlas, it's easy to find an object knowing just its constellation. There are only 109 Messier objects, and only a dozen charts to look at.
Next step: look for a typical 11th-magnitude NGC galaxy in Ursa Major. That's a pretty mundane job; such galaxies are easily visible in most backyard scopes, and UMa probably contains dozens of them. Now you're going to need Sky Atlas 2000.0, or the Pocket Sky Atlas, because you've exceeded the limit of naked-eye atlases. You will still only have a couple of sheets to search, but you'll have to search the entire sheet, because UMa is huge. Fortunately, as I said, NGC objects are arranged in RA order, so it's fairly easy to find out where to go left-right. But you still have to scan all the way up and down -- and as I said, UMa is huge, and packed with galaxies.
Next step. You're looking for the "Footprint Nebula," Minkowski 1-92, in Cygnus. Again, the PSA or SA2K will suffice. But now you have no clue where in this large constellation your nebula lies, and you could spend some serious time looking for it.
And then on to the big time. You're looking for a typical 13th-magnitude galaxy or 14th-magnitude planetary nebula, and you need Uranometria or Millennium. Each constellation covers dozens of pages in the atlas. Without the coordinates, you're totally lost.
Sure, if you use a computer you can find the object by name, assuming it's in the database -- and not all objects will be, no matter what database you use. But if you're using a computer, you can look up the constellation anyway, so the whole discussion is irrelevant.
You *really* need to learn to use celestial coordinates -- and not just to use them, but to get an intuitive feel for them. Otherwise, you will end up crippled.
Essentially all large databases of celestial objects are arranged by RA, whether electronic or hardcopy. It's the only sensible way to do it.
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Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
Sorting by RA is the same as sorting by transit time.
Of course it is! RA *is* transit time. Haven't you ever wondered why it's measured in hours instead of degrees?
I take home two important messages from the whole discussion. First, the importance of constellations, which I never really doubted. To some extent, I've just been playing devil's advocate.
But much more important, how many relatively experienced observers don't understand the fundamentals of celestial coordinates. That's truly a problem. Because while constellations are handy, and come with rich and wonderful historical baggage, celestial coordinates are *essential*. You really can't understand the way the sky works if you don't understand them.
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Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
When I hear "Leo" I immediately think, "Winter mornings, Spring evenings."
Of course you do -- and so do I.
But when you hear RA 11:30, exactly that same thought springs instantly to mind, doesn't it? Of course it does!
If people can memorize the attributes of 88 constellations, they can *certainly* learn when each of the 24 hours of RA is visible.
I may have a bias toward numbers for two reasons. First, I have a strong mathematical intuition. Numbers are alive for me. Taken purely as abstract mathematical entities, each individual number from 1 to 100 has a totally different smell and feel (as it were) from each other number.
Second, having grown up (3/4 time, anyway) in Manhattan, numbers as coordinates are equally alive for me. To take extreme examples, "125th Street" or "Fifth Avenue" are strongly evocative even to non-natives. But to anybody who's actually lived there, the idea that anybody might confuse Sixth and Seventh Avenues, or 59th Street with 57th Street, is ludicrous.
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Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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Hrundi
Pooh-Bah
Reged: 02/06/08
Posts: 1249
Loc: Estonia
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I too like constellations. I have a sort of mental planetarium, so I know when what constellation is where.
I find that by far the least useful way to indicate where an object is, or when it's viewable, is by season.
For those of us who don't stick to just evening 9pm to 11pm observing, or don't have constant stretches of daylight (at my latitude, gets dark at 12am late august, never in june, and 6pm in december), the season is entirely useless. M31 is as much a late summer object as a late winter object, and the era of cygnus is all months that are not december.
As for needing RA for starhopping, I've pulled off 2 degree starhops to a mag 12.3 galaxy in delphinus, as well as starhops to the extent of 4 degrees without so much as ever looking at RA. All it takes is a sense of how your scope works, how the sky is orientated, and if you're looking for an x mag star, what it'd look like in a jumble of fainter stars.
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ursamajor
super member
Reged: 07/24/07
Posts: 145
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For most of us astronomy is a hobby. The use of RA and Dec are more scientific and are obviously essential to pinpoint the location of an object.I suppose that constellations could become redundant but we would lose something. It could mean another lost connection to our past if amateurs no longer used them.
For beginners, school children and the general public the "Big Dipper" is relevant. They can look up years later and identify it.Many I suspect are unaware that it is part of (UMa). Very few would know or care what its RA & Dec is.
From where I sit, adding three letters in brackets after the coordinates seems to be reasonable.
Clear skies;
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Using a goto scope is like fishing with hand grenades...
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BobinKy
Carpal Tunnel
Reged: 04/27/07
Posts: 1683
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Quote:
But much more important, how many relatively experienced observers don't understand the fundamentals of celestial coordinates.
Tony Flanders
Tony, for the second time in this thread, thank you for your comments on the topic of constellations.
I will be the first to admit that I do not understand many--no, make that most--of the fundamentals of celestial observing. But I am (like most of the participants in this forum) trying to learn; which is why we read astronomy books, Sky & Telescope magazine, astronomy links, as well as participate in online astronomy forums. Please keep that in mind as you respond to our posts.
Quote:
Because while constellations are handy, and come with rich and wonderful historical baggage, celestial coordinates are *essential*.
Tony Flanders
As I said in my previous post, I am a constellation guy and probably will always be a constellation guy. I do not consider constellations to be historical baggage. In fact, I do not consider anything historical to be baggage. Those of us who are hobby astronomers learn, live, and breathe astronomy through the lens of constellations. Celestial coordinates are a more precise measure, to be sure, but many amateurs do find constellations sufficient. Particularly, when we also have to struggle with the learning curves of optics and other astronomical issues.
Let me say again, for the record, I do not consider constellations to be baggage. I consider constellations to be essential to my enjoyment of amateur astonomy.
. . .
For those interested in both constellations and celestial coordinates, a good orientation/review is "Chapter 11: Finding you way around the sky" in The Backyard Astronomer's Guide, 3rd ed. (Dickinson & Dyer, 2008, pp. 206-231). This book is published by the fine folks of Firefly Books.
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Bob
38°N
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
I do not consider constellations to be historical baggage.
Sorry, I did not mean the word "baggage" to be pejorative in any way.
I love history, I love history of science, and the history of constellations is especially wonderful because it combines science, literature, and mythology. What more could anyone ask?
Writing the Constellation Closeup column for Night Sky magazine was my very favorite among all the great jobs I've had to do at Sky & Telescope.
There's a reason that my new signature lists naked-eye observing as my first and foremost astronomical love. And naked-eye stargazing without constellations would be like sailing a boat without a keel.
However, the fact that astronomy is rich with culture and history in no way detracts from the fact that astronomy is fundamentally mathematical and scientific, nor vice versa. In fact, astronomy is the *root* of mathematics and science. The Greeks invented trigonometry so that they could do astronomy; Newton invented the calculus so that he could do astronomy; Gauss developed modern mathematics so that he could do astronomy.
Constellations are wonderful, celestial coordinates are wonderful, and the two are intimately entwined. Claudius Ptolemy understood that. Do you?
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Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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BobinKy
Carpal Tunnel
Reged: 04/27/07
Posts: 1683
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Quote:
However, the fact that astronomy is rich with culture and history in no way detracts from the fact that astronomy is fundamentally mathematical and scientific, nor vice versa. In fact, astronomy is the *root* of mathematics and science. The Greeks invented trigonometry so that they could do astronomy; Newton invented the calculus so that he could do astronomy; Gauss developed modern mathematics so that he could do astronomy.
Constellations are wonderful, celestial coordinates are wonderful, and the two are intimately entwined. Claudius Ptolemy understood that. Do you?
Tony Flanders
Actually I am trying to learn math (again, after 40 years). I just purchased some used textbooks and new math references. They may not be the best learning aids, but they were recommended by a math educator. Here is the list if others want to give it a go.Selby, P. H., & Slavin, S. (1991). Practical algebra: A self-teaching guide (2nd ed.). New York: John Wiley & Sons.
Jurgensen, R. C., Brown, R. G., & Jurgensen, J. W. (1990). Geometry. Boston: Houghton Miffin.
Ross, D. A., (2010). Master math: Geometry (2nd ed.). Boston: Course Technology, a part of Cengage Learning.
Ross, D. A., (2010). Master math: Trigonometry (2nd ed.). Boston: Course Technology, a part of Cengage Learning. I also picked up a Texas Instruments scientific calculator (TI-30X IIS), which I am using in conjunction with the Bushnell Legend 1200 ARC rangefinder to measure the heights of trees.
I picked up the used high school Geometry textbook (Jurgensen, Brown, & Jurgensen, 1990) because the first chapter opened with a nifty photograph of an astronomer in an observatory with the following caption. As ancient people studied the heavens, they saw and named many patterns of points, lines, and angles formed by the stars. Although modern astronomers use sophisticated observatories and equipment, they still base their calculations on geometric principles that have been known for many centuries (p. xvi). No, I do not understand the entwinings of astronomy and math. But I am giving it a go at age 60. 
. . .
(Edited Oct. 17, 2009)
The 2009 Willmann-Bell Summer Catalog has a section on "Computational Astronomy" (pp. 13-19). The four books in the Mathematical Astronomy Morsels series written by Jean Meeus (p. 14) looks intriguing.
--------------------
Bob
38°N
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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1075
Loc: Suburban Maryland
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Tony,
Quote:
But when you hear RA 11:30, exactly that same thought springs instantly to mind, doesn't it? Of course it does!
No, it doesn't! Absolutely not. You are joking, aren't you? I doubt very seriously if most amateurs think in terms of RA as you do. It would be interesting to have a poll on CN. Offhand, though, I would guesstimate that most amateurs now fall into three categories as far as how they locate objects: (1) constellation based, with recourse to RA and Dec only when necessary, (2) RA and Dec based primarily, (3) goto or DSC based, with only a very basic knowledge of bright stars and the major constellations, and an appreciation of coordinates only as numbers to enter into the goto machine. I think Category #2 is a small minority. For good or ill, Category #3 is probably fast becoming the majority. I am solidly in Category #1. I'm not sure what the percentage of Category #1s would be, but I'm sure they vastly outnumber the #2s, but are quickly being overwhelmed by the #3s.
Quote:
If people can memorize the attributes of 88 constellations, they can *certainly* learn when each of the 24 hours of RA is visible.
No, not at all. Most people, myself included, are visually oriented and have much more difficulty remembering numbers than visual representations. That's at least partly why the constellations were invented in the first place. For myself, numbers are pretty much dead, lifeless, boring things that have no inherent interest for me. For me to make sure that numbers are securely set in my long term memory, I have to either learn them by rote - it works, but no fun - or use memory techniques which associate the numbers with visual memories. (Google "memory techniques")
Quote:
I may have a bias toward numbers for two reasons. First, I have a strong mathematical intuition. Numbers are alive for me. Taken purely as abstract mathematical entities, each individual number from 1 to 100 has a totally different smell and feel (as it were) from each other number.
Well, then you are clearly the exception. The vast majority of people do not have a strong mathematical intuition or numerical synesthesia. I eny you your ability, but you should remember that most people do not see the world that way at all.
Quote:
Second, having grown up (3/4 time, anyway) in Manhattan, numbers as coordinates are equally alive for me. To take extreme examples, "125th Street" or "Fifth Avenue" are strongly evocative even to non-natives. But to anybody who's actually lived there, the idea that anybody might confuse Sixth and Seventh Avenues, or 59th Street with 57th Street, is ludicrous.
I work with maps and plans all day at my work, and I have maps in my head. But my idiosyncrasy is to recall spatial patterns more than numbers. If I remember the number names of streets or addresses of houses, it's because I associate them with a spatial system in my mind, and to some extent the actual visual memories of those streets. To my mind the numbers are secondary. I don't know how many times I've either chuckled to my self or become exasperated when many people take a plan or map and have to turn it every which way except north up. It's as if they can't understand the plan unless they position it to match the orientation they literally took when they drove into the area. I don't understand why they can't just turn that all around in their minds, and let the plan point north like it's supposed to!
But that may be the same sort of experience you have when amateur astronomers want to know what constellation an object is in rather than just the RA and Dec. As I said, ideally I want all three.
Clear Skies,
Mike
--------------------
Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
Barska XWA 10x50, 8x40
OptiView LPR 10x50
Const View 2.3x40
BV-125C
CG5, 2 drv / CG4, 2 drv, wood legs, ScopeStuff saddle / CG3, 1 drv
SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
QuikFinder, Telrad
Orion Dynamo Pro 12, Dew-Not
Have GLP and not afraid to use it!
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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1075
Loc: Suburban Maryland
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Tony,
Quote:
But much more important, how many relatively experienced observers don't understand the fundamentals of celestial coordinates. That's truly a problem. Because while constellations are handy, and come with rich and wonderful historical baggage, celestial coordinates are *essential*. You really can't understand the way the sky works if you don't understand them.
Probably many of the observers coming up now not only don't understand celestial coordinates, they don't know the constellations! Without goto or DSCs they are truly lost! I have heard too many stories of amateurs that rely soley on goto taking all their toys and going home if they can't get the goto to work. That is more than a little pathetic.
Mike
By the way, I understand celestial coordinates, it's just that I only rely on them when necessary. And they are not always necessary, not by a long shot.
--------------------
Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
Barska XWA 10x50, 8x40
OptiView LPR 10x50
Const View 2.3x40
BV-125C
CG5, 2 drv / CG4, 2 drv, wood legs, ScopeStuff saddle / CG3, 1 drv
SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
QuikFinder, Telrad
Orion Dynamo Pro 12, Dew-Not
Have GLP and not afraid to use it!
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astrokido
space wanderer
Reged: 06/09/08
Posts: 666
Loc: Phoenix, AZ
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Most already know that there's an official definition of the 88 constellations defined in 1930 by the IAU. The constellations were only vaguely defined before then, having no boundaries, only figures made up of stars.
Having clear constellation boundaries was obviously very important to astronomers around the globe. It's still as important today, even if some get lazy about them. I like the term "baggage" and it's the kind of baggage you'd loose a lot if you didn't have it with you.
--------------------
- Gill C. - Celestron Cometron CO-100, 10x25, 20x80, Binochair, Nikon D40
The Night Sky Atlas: www.nightskyatlas.com
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
Most already know that there's an official definition of the 88 constellations defined in 1930 by the IAU. The constellations were only vaguely defined before then, having no boundaries, only figures made up of stars.
Funny you should mention that. I have very mixed feelings about the constellation reforms. They were undertaken to avoid confusion when naming variable stars, which is a perfectly legitimate reason. But in many ways, they violate the traditional sense of what a constellation is. The idea that every point in the sky has to be part of one and only one constellation would have been been very alien to the Greeks who first formalized the constellations that we now know.
Prior to the reforms, many stars were considered to be shared between constellations -- as they intuitively are. A prime case in point is Alpha Andromedae, a.k.a. Delta Pegasi. How can one corner of the Great Square of Pegasus not be in Pegasus? It's preposterous!
Likewise, Ptolemy cataloged a fair number of stars as "between constellations," or "not lying in a constellation."
Then there's the silliness of denying that Scorpio is a legitimate name for the constellation. It's been used interchangeably with Scorpius for millennia!
Prior to the reforms, a constellation was a group of stars -- that's the literal meaning of the word. Now, a constellation is an area of the sky, which it never used to be. And still isn't, to anybody who learns the sky informally.
--------------------
Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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scopethis
professor emeritus
Reged: 05/30/08
Posts: 638
Loc: Kingman, Ks
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All of my "objects viewed" notes are sorted by Constellation, not RA or DEC. And not trying to be a trouble maker, but if I asked someone where they were born and they replied with a long/lat????? say what?
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rookie
scholastic sledgehammer
Reged: 01/14/06
Posts: 881
Loc: St. Petersburg, FL
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Hi Tony
Quote:
You *really* need to learn to use celestial coordinates -- and not just to use them, but to get an intuitive feel for them. Otherwise, you will end up crippled.
Essentially all large databases of celestial objects are arranged by RA, whether electronic or hardcopy. It's the only sensible way to do it.
That's a *really* good idea for a methodical article in S&T or has it already been done? Some advanced observers might think it too prosaic, but the strategies you have already mentioned have been helpful. The postings on this thread indicate it's not second nature to many of us.
I manage hundreds of patient data numbers at work each day. When I look at columns of RA at night, my eyes glaze over. The picture of a constellation has so far worked for me for small sections of the sky but I understand that learning RA is better for the *really* big picture. 
--------------------
SV
Scope: Celestron CPC8
Binoculars: Garrett GT80~45, Fujinon 16x70, Regals 10x42, Ultima 9x63, Nikon AE 8x40
Edited by rookie (10/17/09 07:31 AM)
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BobinKy
Carpal Tunnel
Reged: 04/27/07
Posts: 1683
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There have been many books published about constellations. One fact-filled book written in list format is The Cambridge Guide to the Constellations. The book was written by Michael E. Bakich and published by Cambridge University Press in 1995, when Bakich was Planetarium Director of the Kansas City Museum. Today, Bakich serves as Senior Editor of Astronomy Magazine.
Part 1 (pp. 1-132) provides a variety of constellation lists, such as the Central point of the constellations (pp. 36-38), Extinct constellations (pp. 42-48), Messier objects in numerical order, by constellation, and by right ascension (pp. 51-57), Midnight culmination dates of the constellations (pp. 62-64), 'New' constellations (p. 82), Original 48 constellations (83-84), and Number of visible stars in the constellations (pp. 130-132).
Part 2 (pp. 133-311) presents the same type of information for each constellation, plus black & white illustrations of classic constellation figures and modern charts.
The book concludes with a glossary and list of references.
. . .
Another interesting book is A Constellation Album: Stars and Mythology of the Night Sky written by P. K. Chen and published by Sky & Telescope in 2007.
. . .
And who can overlook Star Tales written by Ian Ridpath, second edition published by Lutterworth Press in 1989. Ridpath's gem is available online at Star Tales: Myths, Legends, and History of the Constellations .
--------------------
Bob
38°N
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Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 12230
Loc: Los Angeles
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Quote:
Quote:
I generally don't use RA and Dec at all when I star hop. If I'm looking at the object's constellation in an atlas, I can spot the object pretty quickly, as long as the NGC or other designation is printed beside it.
That's because you're sticking to warhorses. Sure, if you're looking up Messier objects in the Bright Star Atlas, it's easy to find an object knowing just its constellation. There are only 109 Messier objects, and only a dozen charts to look at.
Next step: look for a typical 11th-magnitude NGC galaxy in Ursa Major. That's a pretty mundane job; such galaxies are easily visible in most backyard scopes, and UMa probably contains dozens of them. Now you're going to need Sky Atlas 2000.0, or the Pocket Sky Atlas, because you've exceeded the limit of naked-eye atlases. You will still only have a couple of sheets to search, but you'll have to search the entire sheet, because UMa is huge. Fortunately, as I said, NGC objects are arranged in RA order, so it's fairly easy to find out where to go left-right. But you still have to scan all the way up and down -- and as I said, UMa is huge, and packed with galaxies.
Next step. You're looking for the "Footprint Nebula," Minkowski 1-92, in Cygnus. Again, the PSA or SA2K will suffice. But now you have no clue where in this large constellation your nebula lies, and you could spend some serious time looking for it.
And then on to the big time. You're looking for a typical 13th-magnitude galaxy or 14th-magnitude planetary nebula, and you need Uranometria or Millennium. Each constellation covers dozens of pages in the atlas. Without the coordinates, you're totally lost.
Sure, if you use a computer you can find the object by name, assuming it's in the database -- and not all objects will be, no matter what database you use. But if you're using a computer, you can look up the constellation anyway, so the whole discussion is irrelevant.
You *really* need to learn to use celestial coordinates -- and not just to use them, but to get an intuitive feel for them. Otherwise, you will end up crippled.
Essentially all large databases of celestial objects are arranged by RA, whether electronic or hardcopy. It's the only sensible way to do it.
I don't know where you observe, but 95% of the people observing where I observe have either GoTo or PushTo on their scopes.
I will go a little further and say that, for most of these people, RA and DEC are the obsolete figures. If you look up and see that a particular constellation is up, you simply type the number of the object into your hand controller or box and the telescope can be moved, or moves, to the object.
Except for rank beginners with very inexpensive scopes, I'd also say that 80+% of all scopes sold today are computerized with one of the two systems for object finding on board.
So the RA and DEC are largely irrelevant and the constellation is all-important.
I've been doing this so long I know where something is in the sky from the RA and DEC figures. But I had non-computerized scopes for 30 years and have used atlases from 1965 on.
To today's beginner with a computerized scope (either GoTo or PushTo), RA and DEC are the figures that confuse and make objects hard to find. By and large, these people do not use atlases at all, and a simple list of objects with a constellation listed is all they need to find something.
They know (I ask hundreds of them over a month) what The Ring Nebula looks like, but they have no idea where it is in the sky unless you say, "It's in Lyra".
Not listing a constellation for a list of objects (or even one object, for that matter) will "exclude" them from looking for the object unless they get lucky and the constellation it's in happens to be well-placed for observing.
If you have to leave out some details due to space, I'd vote for leaving out RA and DEC.
Since that'll never happen, how about adding the constellation to each and every list of objects published.
--------------------
Don Pensack
12.5" Truss Dob, 5" Maksutov, Fujinon Binos
Sustaining Lifetime IDA member
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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1075
Loc: Suburban Maryland
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Don,
Quote:
Except for rank beginners with very inexpensive scopes, I'd also say that 80+% of all scopes sold today are computerized with one of the two systems for object finding on board.
I wholeheartedly agree with and support everything you said in your post except for this sentence. I'm no rank beginner. I've owned and used scopes and binos off and on since the early '70's. But so far, for myself, I haven't seen that it was really cost effective to get goto or DSCs. I could always get more aperture without DSCs, or the aperture that I wanted at the time without DSCs, at a lower price. I know the constellations, how to use an atlas, and how to star hop (with or without RA & Dec), so it's not a big deal to me to be without goto or DSCs. But since the price of these gizmos has gone down somewhat, and hopefully will continue to drop, if and when I buy a 14" or larger truss scope, it will probably have DSCs.
And judging by the sometimes heated threads over goto vs no-goto on CN, I think there are still quite a few star geezers like myself that have opted out of the goto revolution .. for now.
Clear Skies,
Mike
--------------------
Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
Barska XWA 10x50, 8x40
OptiView LPR 10x50
Const View 2.3x40
BV-125C
CG5, 2 drv / CG4, 2 drv, wood legs, ScopeStuff saddle / CG3, 1 drv
SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
QuikFinder, Telrad
Orion Dynamo Pro 12, Dew-Not
Have GLP and not afraid to use it!
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Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 12230
Loc: Los Angeles
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Mike,
I hear you. You're part of a shrinking minority of telescope buyers. I'll go further and state that it is nearly impossible to sell a telescope above $800 that does not have a computer.
I lose sales every day because the dobs I sell don't have on-board computers and somebody else's do.
Sky-Watcher, as one example, heard that, and they're bringing computerized dobs to market. And several companies offer computer add-on kits for some of the commercial dobs.
SCTs all sell with computers.
The one area where computers haven't become the majority of telescope sales inclusions is in the small refractor, grab'n'go models on simple alt-az mounts.
We visual-only observers have become the minority, alas.
--------------------
Don Pensack
12.5" Truss Dob, 5" Maksutov, Fujinon Binos
Sustaining Lifetime IDA member
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rookie
scholastic sledgehammer
Reged: 01/14/06
Posts: 881
Loc: St. Petersburg, FL
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It's hard to learn the sky as a visual-only observer these days because in urban areas you just can't see it anymore. I grew up under dark NELM 6 (and better at 30 below) farm skies, and I know the difference. I wish I had the same opportunities then as I do now.
I agree that the downside of goto is that it gives a person an excuse not to learn the sky. On the other hand, my CPC scope has been my greatest teacher, because my goal is to learn. I observe with skymaps and binoculars too. I have not paid enough attention to RA, but I'm going to from now on. Maybe it will eventually sink in. 
--------------------
SV
Scope: Celestron CPC8
Binoculars: Garrett GT80~45, Fujinon 16x70, Regals 10x42, Ultima 9x63, Nikon AE 8x40
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djeber2
professor emeritus
Reged: 07/02/04
Posts: 733
Loc: Ohio
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You can put me down also as a dinosaur who has no go to scopes, likes to use paper star atlases, find the objects that I observe myself, etc.
--------------------
Don
10" Dob, 4 Small scopes, 2 Classic Scopes (4.25" Edmunds, Sears 60mm), Several Binoculars
Job 9:9 He made the Bear, Orion, and the Pleiades, and the chambers of the south.
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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1075
Loc: Suburban Maryland
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Don,
Quote:
You're part of a shrinking minority of telescope buyers. I'll go further and state that it is nearly impossible to sell a telescope above $800 that does not have a computer.
I know from experience, though, that you can buy plenty of telescopes well under $800 without a computer!
Quote:
I lose sales every day because the dobs I sell don't have on-board computers and somebody else's do. Sky-Watcher, as one example, heard that, and they're bringing computerized dobs to market. And several companies offer computer add-on kits for some of the commercial dobs.
SCTs all sell with computers.
Sometimes I wish I had ordered my 10" Dob with DSCs, but at the time it would have cost about $600 more. My next big scope will probably be at least a 14" with DSCs. But in the meantime there is plenty for me to find and observe the "old-fashioned" way, using constellations, star atlases, charts, Telrads, finders ... and sometimes RAs & Decs. (By the way, the big advantage I see to DSCs is not so much finding the object in the first place - although it would be nice to find it faster and easier - but in re-finding the object quickly after I change eyepieces, add a Barlow or slip in a filter.)
Quote:
We visual-only observers have become the minority, alas.
Star geezers. Sometimes binosaurs?
Mike
--------------------
Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
Barska XWA 10x50, 8x40
OptiView LPR 10x50
Const View 2.3x40
BV-125C
CG5, 2 drv / CG4, 2 drv, wood legs, ScopeStuff saddle / CG3, 1 drv
SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
QuikFinder, Telrad
Orion Dynamo Pro 12, Dew-Not
Have GLP and not afraid to use it!
|
Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
I don't know where you observe, but 95% of the people observing where I observe have either GoTo or PushTo on their scopes.
That's certainly not true in the gatherings that I've attended. Closer to 50%, I'd say. Certainly no more than 75%.
Quote:
You simply type the number of the object into your hand controller or box and the telescope can be moved, or moves, to the object.
A significant fraction of the objects that I look at aren't in any database. Just to pick one example, I try to "do" all of Sue French's Deep-Sky Wonders columns, since I edit her columns. And it's a rare DSW column where all of the objects are listed in a standard database. (Sue has profound knowledge and very eclectic tastes.) Moreover, standard databases often get positions of objects wrong. So everyone is going to, at the very least, need to type RA and Dec into their Go To controllers from time to time.
If nothing else, RA and Dec are indispensable as cross-checks.
Quote:
Since that'll never happen, how about adding the constellation to each and every list of objects published.
I'll consider it seriously *except* in the case of Deep-Sky Wonders. A table with a column where all the entries have the same value is poor design. Especially if the table's title is something like "Deep-Sky Objects in Auriga."
--------------------
Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 12230
Loc: Los Angeles
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Tony,
Yes, the databases of most computers don't contain the innumerable star cluster catalogs that would be useful for most amateurs.
But most contain a significant number of Messier, Caldwell, NGC, IC, UGC, ESO, etc. objects for the observer. The databases are huge compared to the explorations that most telescope owners pursue.
When I'm in the field, I usually find that most computerized telescope owners don't even know how to search for a set of coordinates. Nor do they explore much beyond the Messiers and brightest NGCs.
Articles in a magazine that highlight the best objects to look at in a particular section of sky are wonderful to help expand the viewing programs of less-experienced observers.
Ultimately, it would be great if the computer databases on most scopes contained all the objects visible in the apertures of the scopes on which the databases reside. Instead, they have thousands of objects not visible and are missing thousands of objects that are.
In the meantime, your comments are apropos. Perhaps I see such a high percentage of computer users because I'm in California.
--------------------
Don Pensack
12.5" Truss Dob, 5" Maksutov, Fujinon Binos
Sustaining Lifetime IDA member
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David Knisely
Postmaster
Reged: 04/19/04
Posts: 8290
Loc: Beatrice, Nebraska
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Quote:
Tony,
Yes, the databases of most computers don't contain the innumerable star cluster catalogs that would be useful for most amateurs.
But most contain a significant number of Messier, Caldwell, NGC, IC, UGC, ESO, etc. objects for the observer. The databases are huge compared to the explorations that most telescope owners pursue.
When I'm in the field, I usually find that most computerized telescope owners don't even know how to search for a set of coordinates. Nor do they explore much beyond the Messiers and brightest NGCs.
Articles in a magazine that highlight the best objects to look at in a particular section of sky are wonderful to help expand the viewing programs of less-experienced observers.
Ultimately, it would be great if the computer databases on most scopes contained all the objects visible in the apertures of the scopes on which the databases reside. Instead, they have thousands of objects not visible and are missing thousands of objects that are.
In the meantime, your comments are apropos. Perhaps I see such a high percentage of computer users because I'm in California.
At the Nebraska Star Party, I would say that perhaps 30% of the scopes were Go-to instruments, with a scattering of push-to and DSC equipped Dobs rounding out the rest. This would jive with the 50% figure cited by Tony. As for me, while I could just connect my laptop to the scope and be one-click away from the target, I often pass and just enter the coordinates manually into my NexStar's hand controller. It avoids the silly cable (which I often trip over) and lets me use any source for the coordinates (book, atlas, or laptop). If amateurs don't learn how to use R.A. and Dec., that is their loss. Heck, I had to know the conversions between altitude and azimuth to R.A. and Dec., as well as the conversions to ecliptic and galactic coordinates when I was back in college using only a pocket calculator (and I had to *derive* the equations to satisfy my professor). Oh well, I guess entering a few digits in the hand controller isn't too bad after all. Clear skies to you.
--------------------
David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
Prairie Astronomy Club
http://www.prairieastronomyclub.org
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BobinKy
Carpal Tunnel
Reged: 04/27/07
Posts: 1683
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Quote:
Heck, I had to know the conversions between altitude and azimuth to R.A. and Dec., as well as the conversions to ecliptic and galactic coordinates when I was back in college using only a pocket calculator (and I had to *derive* the equations to satisfy my professor).
David Knisely
David...
By chance, do you still have your college equations to convert coordinates (horizon<-->equatorial<-->ecliptic<-->galactic)? 
. . .
Hey--I just checked my observation planning software (SkyTools 3) and it gives me the following coordinates for M31.Coordinates for M31 -- SkyTools 3
Equatorial . . . . . RA 00h42m44.3s, DEC +41°16'07"
Equatorial Apparent . . . . . RA 00h43m18.9s, DEC +41°19'36"
Ecliptic . . . . . LON +27°50'54", LAT +33°20'57"
Galactic . . . . . LON +121°10'27", LAT -21°34'24"
Hour Angle . . . . . 00h01m
Horizon (Bob's Backyard, Oct. 19, 2009 12:30 am) . . . . . ALT +86°51', AZM +359°35'
Constellation . . . . . Andromedia
Paper Atlas Chart Numbers
Sky Atlas 2000.0 . . . . . 4
Millennium Star Atlas . . . . . I-105
Uranometria 2000.0 (1st ed.) . . . . . I-60
Uranometria 2000.0 (2nd ed.) . . . . . 30
Pocket Sky Atlas . . . . . 3
Herald Bobrof Astroatlas . . . . . B-03 C-38 I am a visual observer who observes by naked eye, binoculars (hand held or alt/azm mount), or telescopes (alt/azm mounts). Like many of the other people posting replies in this thread, I primarily use the coordinate information of horizon and constellation. I find a field compass, planisphere, and paper atlas to be all I need. At times I use the equatorial coordinates provided by SkyTools 3 to locate objects on the paper charts. However, it is nice to know that if I get an equatorial mount or goto scope, I can use the coordinates.
. . .
The History and Practice of Ancient Astronomy (Evans, 1998, pp. 99-105) provides a short overview of the horizon, celestial (equatorial), and ecliptic coordinate systems.
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Bob
38°N
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blb
sage
Reged: 11/25/05
Posts: 219
Loc: Piedmont NC
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Quote:
David...
By chance, do you still have your college equations to convert coordinates (horizon<-->equatorial<-->ecliptic<-->galactic)?
Yes, I would be interested in them too!
Thanks, Buddy
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C-11, C-6, XT10i Dob, ETX125PE, TV102, & AT66
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David Knisely
Postmaster
Reged: 04/19/04
Posts: 8290
Loc: Beatrice, Nebraska
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Quote:
Quote:
Heck, I had to know the conversions between altitude and azimuth to R.A. and Dec., as well as the conversions to ecliptic and galactic coordinates when I was back in college using only a pocket calculator (and I had to *derive* the equations to satisfy my professor).
David Knisely
David...
Do you still have your college equations to convert coordinates (horizon<-->equatorial<-->ecliptic<-->galactic)?
. . .
Hey--I just checked my observation planning software (SkyTools 3) and it gives me the following coordinates for M31.Coordinates for M31 -- SkyTools 3
Equatorial . . . . . RA 00h42m44.3s, DEC +41°16'07"
Equatorial Apparent . . . . . RA 00h43m18.9s, DEC +41°19'36"
Ecliptic . . . . . LON +27°50'54", LAT +33°20'57"
Galactic . . . . . LON +121°10'27", LAT -21°34'24"
Hour Angle . . . . . 00h01m
Horizon (Bob's Backyard, Oct. 19, 2009 12:30 am) . . . . . ALT +86°51', AZM +359°35'
Constellation . . . . . Andromedia
Paper Atlas Chart Numbers
Sky Atlas 2000.0 . . . . . 4
Millennium Star Atlas . . . . . I-105
Uranometria 2000.0 (1st ed.) . . . . . I-60
Uranometria 2000.0 (2nd ed.) . . . . . 30
Pocket Sky Atlas . . . . . 3
Herald Bobrof Astroatlas . . . . . B-03 C-38 I am a visual observer who observes by naked eye, binoculars (hand held or alt/azm mount), or telescopes (alt/azm mounts). Like many of the other people posting replies in this thread, I primarily use the coordinate information of constellation and/or horizon. I find a field compass, planisphere, and paper atlas to be all I need. At times I use the equatorial coordinates provided by SkyTools 3 to locate objects on the paper charts. However, it is nice to know that if I get an equatorial mount or goto scope, I can use the coordinates.
. . .
The History and Practice of Ancient Astronomy (Evans, 1998, pp. 99-105) provides a short overview of the horizon, celestial (equatorial), and ecliptic coordinate systems.
I am on vacation at my parent's house right now, so my old astronomy notebooks that have the equations are about 300 miles away. However, there should be some on-line sources for the common coordinate conversion equations (Wikipedia has horizon, equatorial, ecliptic, and galactic conversions). I think that there are at least several books that have them (some by Peter Duffet-Smith IIRC). Astronomical Algorithms by Jean Meeus also has some of these. Clear skies to you.
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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
Prairie Astronomy Club
http://www.prairieastronomyclub.org
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
Heck, I had to know the conversions between altitude and azimuth to R.A. and Dec., as well as the conversions to ecliptic and galactic coordinates when I was back in college using only a pocket calculator (and I had to *derive* the equations to satisfy my professor).
Yuck! I'm quite sure that I could derive the equations to convert between different spherical coordinate systems from first principles, and I also know several places where I can look them up. But perhaps precisely because the conceptual difficulties are so small, I feel not the slightest desire to do the work myself. Basically, that would be a choice to convert myself from a thinking human being into a computer -- and a very inferior one, too.
Same is *not* true for being able to estimate what season to observe an objects based on its RA. Once you've acquired that skill, it takes just a split second to do that, which is far less time than it would take to key the information into a computer.
There are places where using a computer is life-enhancing and places where it's life-diminishing. Not necessarily the same for every person, of course. But when in any serious doubt, it's always best not to get too dependent on machines -- they're always itching to take over your life and convert you into a couch potato. That goes for cell phones, computers, cars, and even bicycles.
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Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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desertstars
Please stand by...
Reged: 11/05/03
Posts: 34598
Loc: Tucson, AZ
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Somehow, the idea of a bicycle turning me into a couch potato seems a bit counter-intuitive.
Otherwise, we more or less agree.
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Tom W.
Collinder's Catalog
Jewels in Dark Settings
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
Somehow, the idea of a bicycle turning me into a couch potato seems a bit counter-intuitive.
Bicycle is my normal way to get from one place to another. But bicycles are so fast, and the distances I cover are so small, that when I use bicycle only, it feels first of all as though I'm getting no exercise and second as though I'm missing much of the stuff that goes on around me. So I've made a major effort in the last few years to use my bicycle less.
Bicycles are *way* too fast to really see the fine details of your environment. Our species is defined by the fact that we walk on two legs, and when we stop walking, we lose much of our common heritage.
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Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
Edited by Tony Flanders (10/19/09 01:38 PM)
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llanitedave
Humble Megalomaniac
Reged: 09/26/05
Posts: 12945
Loc: Amargosa Valley, NV, USA
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At the Death Valley Star Party this past weekend there were a large number of tourists present, many who had barely ever seen the stars at all, much less through a telescope.
I was on the tarmac surrounded by scopes with GoTo and DSCs, when a couple of attractive (in the dark) young women stopped by and asked if I was looking at anything. I showed them the Ring Nebula and asked if they'd seen the Andromeda Galaxy yet. They hadn't, so I grabbed my UTA whipped it around, sighted in through the Telrad, and invited them to look. After seeing all the automated, computerized instruments in action, they were amazed and delighted by my "expertise" in manually pointing the scope. "How did you do that?!", they squealed.
Had I been young and single, I would have been in geek heaven.
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"Since the process of science generates more mysteries than it solves, I predict that we'll never learn everything: and we'll continue to generate new ignorance at the speed of knowledge."
"S.O.E." (Sauron's Other Eye), with 16" Royce conical mirror: A permanent work in progress.
10" Homebuilt dob, old Coulter mirror
Under Construction: The "Eye of Sauron" Observatory!
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scopethis
professor emeritus
Reged: 05/30/08
Posts: 638
Loc: Kingman, Ks
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OK Tony, your suggestion is positive. Title the column as objects in "whatever" Constellation, then list the RA, DEC, size, mag, and type, etc. I still use an old LX50 scope with the Magellen II. It's not super accurate, I still have to hunt (which I did with scopes before GOTO/Electric Digital Circles) and it doesn't bother me. And I still have to use RA/DEC and charts/atlas when objects aren't in the data base.
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BobinKy
Carpal Tunnel
Reged: 04/27/07
Posts: 1683
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This thread presents aspects of both mathematical astronomy and cultural astronomy.
Yes, most of us agree equatorial coordinates are more accurate. But that may not be the issue.
We can choose to see constellations as a tool used by many amateur astronomers for finding their way through the sky, our celestial sphere. We can also choose to see constellations as a bridge to finding our way back to past night sky observers, and to other cultures.
I hope astronomy publications continue to use constellations out of respect for those of us who use them in our hobby. I also hope astronomy publications continue to use constellations out of respect for the past.
. . .
And yes, constellations must be dear and true to Tony's heart, as here is a nice article he wrote for Sky & Telescope online: Constellation Names and Abbreviations .
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Bob
38°N
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Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 12230
Loc: Los Angeles
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A minor segue:
I seem to recall an article several years ago that discussed the historical age of each constellation in relation to precession.
The author was arguing that different constellations were more prominent in the sky at different times in history and that the importance of those constellations related to the orientation of the cultures that created the constellation patterns at the time.
I seem to remember Capricornus and Aquarius, the "Water constellations" as being prominent and important in the time of Babylon (with its dependence on river travel), and Leo during the time of the Assyrians, etc. I'm sure I'm not remembering the details accurately, but you get the idea.
The author argued that some of the major constellations may have gone into the past 10,000 years or more.
Perhaps someone else can refresh my memory as to who the author was.
The point was that constellations are archeological cultural remnants.
As Shelley penned:
"I met a traveller from an antique land
Who said: "Two vast and trunkless legs of stone
Stand in the desert. Near them on the sand,
Half sunk, a shattered visage lies, whose frown
And wrinkled lip and sneer of cold command
Tell that its sculptor well those passions read
Which yet survive, stamped on these lifeless things,
The hand that mocked them and the heart that fed.
And on the pedestal these words appear:
`My name is Ozymandias, King of Kings:
Look on my works, ye mighty, and despair!'
Nothing beside remains. Round the decay
Of that colossal wreck, boundless and bare,
The lone and level sands stretch far away".
There is nothing left of those cultures save the constellations bequeathed to us. We owe them to preserve the constellations for all time.
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Don Pensack
12.5" Truss Dob, 5" Maksutov, Fujinon Binos
Sustaining Lifetime IDA member
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
We can choose to see constellations as a tool used by many amateur astronomers for finding their way through the sky, our celestial sphere. We can also choose to see constellations as a bridge to finding our way back to past night sky observers, and to other cultures.
Well said! Constellations are both of those things -- and more.
One of the reasons that naked-eye is my favorite kind of astronomy is that I feel a direct connection not only with Claudius Ptolemy, but even with Odysseus, sitting by a fire at night telling stories as "the stars wheel down," in Homer's wonderful phrase.
That's also a big part of the reason that I love star-hopping.
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Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
I seem to recall an article several years ago that discussed the historical age of each constellation in relation to precession.
The author was arguing that different constellations were more prominent in the sky at different times in history and that the importance of those constellations related to the orientation of the cultures that created the constellation patterns at the time.
I seem to remember Capricornus and Aquarius, the "Water constellations" as being prominent and important in the time of Babylon (with its dependence on river travel), and Leo during the time of the Assyrians, etc.
Wow, that's taking a well-worn argument and stretching it far beyond credibility. Yes, there's little doubt that many of the zodiacal constellations date back to ancient Mesopotamia -- we can conclude this based just on their names. One or two (Lion, Scorpion) might be coincidence, but not eight or ten. And yes, the sky looked quite different then due to precession.
But I've never seen any truly compelling evidence about exactly when the Mesopotamian constellations were codified, plus or minus a millennium or so.
Brad Schaeffer claims to be able to pinpoint the constellations' origins with a few degrees of latitude and a couple of centuries based on internal evidence, but hardly anybody else believes him.
Quote:
The author argued that some of the major constellations may have gone into the past 10,000 years or more.
That would be Ursa Major, no doubt, due to the fact that it appears to be common between the New World and the Old, with common roots dating back to when the Bering Land Bridge was above water. An interesting speculation, but doomed to remain speculation forever. And with plenty of compelling counter-arguments, too.
Having said all that, the main constellations are indisputably anywhere from very old to very, very, very old.
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Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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Jay_Bird
scholastic sledgehammer
Reged: 01/04/06
Posts: 959
Loc: Nevada 36N 115W
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What a great set of comments that illustrate the appeal of astronomy to both the 'left-brain' and the 'right-brain'.
I had a moment like Dave's back in high school when a club leader of great enthusiasm and organizational skill forgot his atlas and books, and was at a loss for using his orange C8 with the setting circles he normally relied on. We starhopped our way to the brighter visible Messiers based on my recollection as he said "teapot? oh - I see" "flowerpot? (M-13&92), Antares?..." etc.
No one has yet made this simple analogy either:
If I were navigating I might speak in Lat. and Long. or Road and Highway numbers. If telling someone about of trip I talk about city, state, country or continent; a usage more like speaking of constellations, and one also more connected to culture and history.
Ideally, people should have an understanding of both aspects as Tony and others have said. The extra effort to learn either the math or the lore (whichever did not come as easily) will enhance overall understanding.
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'these things stand like stone - kindness in another's troubles, courage in your own' Gordon
C-8, Nighthawk, C-90; Binoculars 6-11x21-80mm; Paragon p-mount
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Rick Woods
Postmaster
Reged: 01/27/05
Posts: 5684
Loc: Inner Solar System
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This brings to mind (again) Walter Scott Houston's preface to the Uranometria 2000 Deep Sky Field Guide, where he says something on the order of "the constellations are nothing but an obstacle to today's fast-track Observers". I've never understood what he meant by that statement. I can't think of a single way in which the constellations could be an obstacle to anyone.
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- Rick
14" LX200GPS
Dyslexics Untie!
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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1075
Loc: Suburban Maryland
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Rick,
IMHO, Walter Scott Huston was incorrect. For me, and probably for many (most?) observers, the constellations are at least a tried-and-true memory aid. They are a celestial analogy of the ancient method of loci, in which visualizing an arrangement of rooms in a building, shops on a street, etc., will help you recall a series of objects. But the constellations are even more helpful than mere loci because they and their spatial relationships actually represent what can be seen by the naked eye. Whether we like it or not, people are for the most part visually-oriented. Coordinates just don't have the same intrinsic interest for the mind and imagination for most people that consellations do.
Clear Skies,
Mike
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Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
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OptiView LPR 10x50
Const View 2.3x40
BV-125C
CG5, 2 drv / CG4, 2 drv, wood legs, ScopeStuff saddle / CG3, 1 drv
SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1075
Loc: Suburban Maryland
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Tony,
Quote:
Quote:
The author argued that some of the major constellations may have gone into the past 10,000 years or more.
That would be Ursa Major, no doubt, due to the fact that it appears to be common between the New World and the Old, with common roots dating back to when the Bering Land Bridge was above water. An interesting speculation, but doomed to remain speculation forever. And with plenty of compelling counter-arguments, too.
The common interpretation between the New & Old Worlds of Ursa Major and Ursa Minor as long-tailed bears always seemed to me to be too much of a coincidence not to have some cultural connection. If it is just a coindidence, it is a very weird coincidence. Do any bears - or did any bears - actually have long tails? Wouldn't it have made more sense for the ancient Amerindians to have seen UMa & UMi as opposum or some other animal that actually has a long tail? And why would peoples of the Old World see those constellations as long-tailed bears in any case, since bears do not have long tails? I can't help but think there was some cultural contact at some point, either in the distant past when the proto-Amerindians were still in Asia, or some early contact with Europeans while in the New World.
Another constellation that must be very old, but probably not as old as the Bears, is Capricornus, the Sea-Goat. Just what is a "Sea-Goat?" Some bizarre water god of ancient Babylonia, I suppose.
Clear Skies,
Mike
--------------------
Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
Barska XWA 10x50, 8x40
OptiView LPR 10x50
Const View 2.3x40
BV-125C
CG5, 2 drv / CG4, 2 drv, wood legs, ScopeStuff saddle / CG3, 1 drv
SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
QuikFinder, Telrad
Orion Dynamo Pro 12, Dew-Not
Have GLP and not afraid to use it!
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astrokido
space wanderer
Reged: 06/09/08
Posts: 666
Loc: Phoenix, AZ
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Referring to the constellations as an obstacle is reducing the sky to a lame celestial sphere. Others see the entire history of human civilization in the constellations.
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- Gill C. - Celestron Cometron CO-100, 10x25, 20x80, Binochair, Nikon D40
The Night Sky Atlas: www.nightskyatlas.com
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
The common interpretation between the New & Old Worlds of Ursa Major and Ursa Minor as long-tailed bears always seemed to me to be too much of a coincidence not to have some cultural connection. If it is just a coindidence, it is a very weird coincidence.
Agreed -- especially since bears are among the very few quadrupeds that *don't* have long tails.
However, it's worth remembering that this particular interpretation was very far from universal in the Old World, and was restricted to a tiny handful among the thousands of New World tribes. It's easy to find coincidences if you have a big enough sample to chose from.
Quote:
I can't help but think there was some cultural contact at some point, either in the distant past when the proto-Amerindians were still in Asia, or some early contact with Europeans while in the New World.
Early contact with Europeans is pretty much out of the question. No Europeans before the Vikings had the necessary technology, and we have pretty good records of just how little the Vikings affected North America.
A far more plausible route would be via the Bering Strait. There's been vigorous travel and trade between Siberia and Alaska at least since the Inuit first arrived a millennium ago. Japanese artifacts got to British Columbia long before any white man did.
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Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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scopethis
professor emeritus
Reged: 05/30/08
Posts: 638
Loc: Kingman, Ks
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My thought on Walter's statement was that the younger generation wants things instantly. Taking the time to learn the Constellations (or muliplication tables) is an "obstacle".
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-=BB=-
only get better
Reged: 07/25/08
Posts: 34
Loc: Connecticut, US
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I would love to get a more intuitive feel for RA and Dec coordinates. I'm fairly new at this hobby, learning my way around the sky via constellations. I know what RA and Dec are as I've read a few pieces - book chapters, magazine articles - about celestial mechanics, but I have no feel for their actual usage, other than I know where Polaris is and I have a rough idea where the ecliptic is located.
I have a number of small scopes now, but they're all fully manual and I have no COL of any kind so I just assumed that coordinates were of little use for my level of observing.
Constellations are certainly handy for identifying bright patches of stars, but there are no hash/hatch marks in the sky.
Maybe this could be a topic for a future S&T article? Something not just describing the coordinate system, but how to actually begin to learn it, use it, know it, and incorporate it into amateur observing?
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~Bruce
"It is at is because it wants, once and for all, to be as it is." - Arthur Schopenhauer, 1788-1860
I have: a 6" Dob, an 80ED Apo, a homemade 70mm refractor, a pair of 10x50 binos and some other stuff.
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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1075
Loc: Suburban Maryland
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BB,
Quote:
Maybe this could be a topic for a future S&T article? Something not just describing the coordinate system, but how to actually begin to learn it, use it, know it, and incorporate it into amateur observing?
Yes, that should be an interesting and very useful article for S&T. [Tony: What do you think? ... hint, hint ... ]
Clear Skies,
Mike
--------------------
Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
Barska XWA 10x50, 8x40
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Const View 2.3x40
BV-125C
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SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
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Have GLP and not afraid to use it!
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Starman1
Vendor - Scope City
Reged: 06/24/03
Posts: 12230
Loc: Los Angeles
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One of my "rough" methods of figuring out where in the sky a particular RA is follows:
0H has to be the Spring Equinox, which is in Pisces
6H has to be the Summer Solstice, which is in Gemini
12H has to be the Autumnal Equinox, which is in Virgo
18H has to be the Winter Solstice, which is in Sagittarius.
Now, are you familiar with which constellations are north, south, east, and west of those constellations?
Then you can know approximately where in the sky a particular hour angle is.
After a while, you also begin to know where in the sky an object is by its NGC number. For example, if its 0-100 it has to be near 0H. If it's ~4000, it's going to be near 12H.
And so on.
Part of it is remembering the NGC numbers for an object rather than the Messier or Proper Name designations. That comes with time and experience. I wouldn't expect a newbie to know where things are in the sky based on the NGC number, but somewhere along the way, you realize that NGC numbers increase with RA. So if you can pinpoint where in the sky an RA is, and you know there are approximately 8000 NGC objects, everything else follows.
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Don Pensack
12.5" Truss Dob, 5" Maksutov, Fujinon Binos
Sustaining Lifetime IDA member
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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1075
Loc: Suburban Maryland
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Don,
All good advice. I have to admit that I knew the RA and constellation of the Spring Equinox, and the directions that the RA increases/decreases in the sky, but that's about it off the top of my head. It would make sense to memorize the RA of each solstice and equinox and their constellations. I already know the spatial relationships among the constellations, so that would help in figuring out the RA of the rest when needed. The tip about the relationship between the NGCs and the RA is also helpful. Of course, for myself and probably most people, it's easier to remember the Messier number and common names of objects rather than the NGCs, for those objects that do have M numbers and/or common names. I recall some of the NGCs because they do not have M numbers and are objects I've observed a number of times. If I wanted to, I could always memorize more of the NGCs via memory techniques in which each 4-digit number can be represented by a visualizied object or at most a pair of objects. If I wanted to ....
Clear Skies,
Mike
--------------------
Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
Barska XWA 10x50, 8x40
OptiView LPR 10x50
Const View 2.3x40
BV-125C
CG5, 2 drv / CG4, 2 drv, wood legs, ScopeStuff saddle / CG3, 1 drv
SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
QuikFinder, Telrad
Orion Dynamo Pro 12, Dew-Not
Have GLP and not afraid to use it!
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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1075
Loc: Suburban Maryland
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Just for fun, here are some NGCs and possible visual representations of the numbers using a famous memory techique:
7009 (Saturn Nebula): Case-Soap
457 (Owl Cluster): Relic
7000 (North America Nebula): Cases
2392 (Eskimo Nebula): Nome-Pan (or -Bun or -Pin)
3242 (Ghost of Jupiter): Moon-Ruin
To remember that 7009 Saturn Nebula is in Aquarius: Saturn washes with Case-Soap and water from Aquarius.
OK, that's enough. Too much off thread.
Mike
--------------------
Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
Barska XWA 10x50, 8x40
OptiView LPR 10x50
Const View 2.3x40
BV-125C
CG5, 2 drv / CG4, 2 drv, wood legs, ScopeStuff saddle / CG3, 1 drv
SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
QuikFinder, Telrad
Orion Dynamo Pro 12, Dew-Not
Have GLP and not afraid to use it!
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
Maybe this could be a topic for a future S&T article? Something not just describing the coordinate system, but how to actually begin to learn it, use it, know it, and incorporate it into amateur observing?
I must admit that I have a bad feeling about it. Somehow, the whole subject seems more appropriate for a book than a magazine. I can't imagine how to discuss it without being didactic and maybe a little boring.
I'll ask Alan MacRobert, though. If anybody could write something like that in a light, accessible style, then he's the guy.
--------------------
Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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rookie
scholastic sledgehammer
Reged: 01/14/06
Posts: 881
Loc: St. Petersburg, FL
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I asked a friend of mine who is the Prof Chair of astronomy at the local college and planetarium if he had any lesson plans for teaching RA or Celestial Coordinate knowledge and his response was, "Why, no!" Then I was served his vague dry humor description, "Pisces is 0 and Orion 5 1/2 or thereabouts". 
We did both agree that the S&T Pocket Sky Atlas is probably a great study guide for this purpose due to its organization.
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SV
Scope: Celestron CPC8
Binoculars: Garrett GT80~45, Fujinon 16x70, Regals 10x42, Ultima 9x63, Nikon AE 8x40
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BobinKy
Carpal Tunnel
Reged: 04/27/07
Posts: 1683
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Planispheres
There has not been a lot of talk in this thread about planispheres (possibly one or two references). I thought I would say a few words about this simple, yet effective instrument to estimate locations of constellations, bright stars, Messiers, and RA and DEC coordinates.
How I use a planisphere to estimate RA in the night sky
The way I estimate RA in the night sky is to use a planisphere, along with a watch and a field compass.
The field compass marks the fixed meridian or transit line (North-South line passing from the Northern horizon through zenith to the Southern horizon). While the RA hours do change throughout the night, the meridian is permanent from a single observing position. However, if I move to a new observing position on the ground, I need to take a new meridian reading.
The hole in the center of the planishere is Polaris, the North star, from which all RA lines radiate. I rotate the planisphere to align the current month, day, and time.
Next, I hold the planishpere up against the sky with the hole in the center covering the actual North Star in the sky. The lines and tick marks on the planisphere for each of the 24 RA hours enable me to estimate the position of RA hours in the night sky radiating from the North Star. The planishere also has DEC tick marks for estimating DEC°.
As the time changes throughout the night, I rotate the planisphere to align the new time with the month and date, and again hold the planisphere over the actual North Star in the sky to estimate the new RA postions.
Observing at meridian
Now is a good time to bring in the oft-quoted and long out-of-print 1001 Celestial Wonders, 3rd ed. (Barnes, 1931), a well written observing guide for keeping one's telescope fixed at meridian over the course of 12 months. Read the magic as the RA 5th hour transits Barnes's meridian on January 13, 1926, at 9 p.m. (p. 51).For who would acquire a knowledge of the heavens in little, let him give up his days and nights to the marvels of Orion. Here may be found every conceivable variation of celestial phenomena: stars, giants and dwarfs; variables, doubles, triples, multiples; binaries visual and spectroscopic; clusters wide and condensed; mysterious rayless rifts and nebulae in boundless variety, with the supreme wonder of all supernatural wonders at its heart--the Great Nebula--before which the learned and the laymen alike have stood silent in awe and reverence since the first lens unfolded to man's gaze its true vastness and intricacy; and which offers abundant field for all the geniuses of science, with their super-refinements of means and methods, for generations to come. To know Orion is to know astronomy! Which planisphere do I use?
I prefer David Chandler's The Night Sky planisphere over other planispheres because it has lines and tick marks for each of the 24 RA hours and every 10° of DEC. Some planispheres I have seen only have lines for every 3 RA hours. In addition to RA and DEC, most planispheres also have visible Constellations marked, as well as many bright stars and Messiers.
If I am sitting at my desk and want to consult a planisphere, I often use the planisphere views in the SkyTools 3 software program or reach for Sky & Telescope's Star Wheel.
In my easy chair, when I read an astronomy magazine or observing guide, I like to have S&T's Star Wheel at my side because of its large size and colorful sky background printed on heavy cardboard. As I read about an interesting star or DSO, I pick up the planisphere to find out when it will be visible from my location.
However, for outside use in the dark, I prefer David Chandler's planisphere because of its simplicity and plastic material.
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Bob
38°N
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rmollise
Post Laureate
Reged: 07/06/07
Posts: 4598
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Quote:
I must admit that I have a bad feeling about it. Somehow, the whole subject seems more appropriate for a book than a magazine. I can't imagine how to discuss it without being didactic and maybe a little boring.
I'll ask Alan MacRobert, though. If anybody could write something like that in a light, accessible style, then he's the guy.
It's not hard to teach the celestial coordinate system, and you don't have to be boring and pendantic either (as if I could _be_ pedantic  ). In fact, I do it every semester in about half an hour--tops.
Think them younguns needs some larnin' in this regard? Do a presentation or two on the subject for your club.
--------------------
Uncle Rod
Rod's New Book:
Choosing and Using a New CAT
Available now!
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auriga
scholastic sledgehammer
Reged: 03/02/06
Posts: 795
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Quote:
Quote:
Maybe this could be a topic for a future S&T article? Something not just describing the coordinate system, but how to actually begin to learn it, use it, know it, and incorporate it into amateur observing?
Tony,
I think it definitely adds something for an observer to be able to think in terms of RA and Dec in locating objects.
And this thread has turned out to be a wonderful discussion.
But for Sky & Telescope's charts, Steve Coe and Tom Polakis and Don Pensack have told you that using a three letter constellation abbreviation is very helpful. I guess they are what you would call "relatively experienced observers?"
It is impressive to learn that you and other fine observers can derive the equations for turning alt and az into RA and Dec, but for me the issue is what observers actually find helpful in locating objects. It appears that in addition to their cultural and historical importance, constellations are widely used by observers in locating objects. How people actually think is quite important, not just how one imagines that they should think if they were wonderfully logical.
Clear skies,
Bill Meyers
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
How people actually think is quite important, not just how one imagines that they should think if they were wonderfully logical.
Well said!
But carrying the discussion of Go To scopes a tad farther. People have given me compelling evidence that RA and Dec are alien to many Go-To users. I may deplore that, but even as influential a force as Sky & Telescope can't change it -- at best, just budge it a little.
However, I betcha that a mighty lot of Go To users also have zero sense of constellations. I wonder whether constellations are genuinely useful for the majority of Go To users. Of course, at three letters, it's worth supplying them even if they're only helpful to a minority.
Regardless, not giving RA and Dec is genuinely unthinkable. Those are *the* rock-bottom identifying data for an object. More important even than the name, which is often ambiguous and open to interpretation.
--------------------
Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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auriga
scholastic sledgehammer
Reged: 03/02/06
Posts: 795
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(snip)
The point was that constellations are archeological cultural remnants.
(snip of a beautiful poem by Shelley.)
There is nothing left of those cultures save the constellations bequeathed to us. We owe them to preserve the constellations for all time.
Don,
Eloquent. Thank you.
Bill Meyers
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BobinKy
Carpal Tunnel
Reged: 04/27/07
Posts: 1683
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--------------------
Bob
38°N
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
(snip)
The point was that constellations are archeological cultural remnants.
(snip of a beautiful poem by Shelley.)
There is nothing left of those cultures save the constellations bequeathed to us. We owe them to preserve the constellations for all time.
A *great* deal remains to us of ancient Mesopotamia, the culture that gave us the most constellations. Writing. Cities. Mathematics. The 360-degree circle. Gilgamesh. Astronomy and astrology. Judaism, and through that, Christianity and Islam.
Astrology is one tradition that we might be better off without.
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Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
Edited by Tony Flanders (10/25/09 08:26 AM)
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BobinKy
Carpal Tunnel
Reged: 04/27/07
Posts: 1683
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Using constellations to measure the sky or to show respect for previous cultures is NOT astrology.
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Bob
38°N
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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1075
Loc: Suburban Maryland
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Tony,
I think your tongue may have been a bit in your cheek, so to speak, but astrology is one tradition that we definitely WOULD be better off without. It is utter and absolute nonsense, and that is not just my humble opinion! I refuse to give anyone my astrological sign if they ask for it, and I purposely make sure not to even glance at the horoscopes in the papers. Don't feed the monster. The fault is in our selves, not the stars.
Going back on topic ......
Clear and Natural Skies,
Mike
--------------------
Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
Barska XWA 10x50, 8x40
OptiView LPR 10x50
Const View 2.3x40
BV-125C
CG5, 2 drv / CG4, 2 drv, wood legs, ScopeStuff saddle / CG3, 1 drv
SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
QuikFinder, Telrad
Orion Dynamo Pro 12, Dew-Not
Have GLP and not afraid to use it!
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
I think your tongue may have been a bit in your cheek, so to speak, but astrology is one tradition that we definitely WOULD be better off without. It is utter and absolute nonsense ...
Of course. However, it's a matter of record that mathematics and science -- and astronomy in particular -- were developed largely because of the desire to do better astrology. And it is also a matter of record that some of the best minds that the world has ever seen devoted much of their effort to astrology.
So people who *really* care about history and tradition for its own sake would be well advised to learn a little about astrology. From the viewpoint of utility, constellations are far superior. But from the viewpoint of antiquity, majesty, and continuity, astrology is equally impressive.
--------------------
Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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-=BB=-
only get better
Reged: 07/25/08
Posts: 34
Loc: Connecticut, US
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Thank you, BobinKY, rookie and starman1 (Don) for the tips. I do have the Pocket Sky Atlas and Don Chandler's planisphere and I shall pay more attention to the information already at my fingertips.
Should anyone wish to pen an article, here on Cloudy Nights, or in S&T or Astronomy, or a chapter in Skywatch, or something in Guy Ottewell's calendar (maybe there already is - I'll have to check), you have at least one interested reader.
Many happy photons to you all.
--------------------
~Bruce
"It is at is because it wants, once and for all, to be as it is." - Arthur Schopenhauer, 1788-1860
I have: a 6" Dob, an 80ED Apo, a homemade 70mm refractor, a pair of 10x50 binos and some other stuff.
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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1075
Loc: Suburban Maryland
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Tony,
Quote:
Quote:
I think your tongue may have been a bit in your cheek, so to speak, but astrology is one tradition that we definitely WOULD be better off without. It is utter and absolute nonsense ...
Of course. However, it's a matter of record that mathematics and science -- and astronomy in particular -- were developed largely because of the desire to do better astrology. And it is also a matter of record that some of the best minds that the world has ever seen devoted much of their effort to astrology.
Also, chemistry developed from alchemy, and some great minds, such as Sir Isaac Newton, worked actively in alchemical research. But both alchemy and astrology are based on supernatural interpretations of natural phenomena and should be rejected as nonsense in the modern world. There is no place for either of these now except as historical curiosities. They should be studied in the same way, perhaps, that dead languages are often learned today, as a way to understand premodern worldviews and as antecedents of modern languages.
Quote:
So people who *really* care about history and tradition for its own sake would be well advised to learn a little about astrology. From the viewpoint of utility, constellations are far superior. But from the viewpoint of antiquity, majesty, and continuity, astrology is equally impressive.
Astrology is an intricate web of deductions, some logical but mostly one form or another of magical thinking, based on a set of misguided interpretations of what we see when we look at the sky at night. I am not impressed by astrology at all, but only feel a twinge of disgust at a pathetic and stubbornly-held mistake inflicted upon a suffering but easily-duped humanity. Should we study prenology because it foreshadowed the scientific knowledge that different areas of the brain have different functions?
What other valid, scientific discoveries and mathematical developments could Newton have made if he had ignored alchemy and "prognostication"? A huge waste of time and effort on utter nonsense best ignored.
Clear Skies,
Mike
--------------------
Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
Barska XWA 10x50, 8x40
OptiView LPR 10x50
Const View 2.3x40
BV-125C
CG5, 2 drv / CG4, 2 drv, wood legs, ScopeStuff saddle / CG3, 1 drv
SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
QuikFinder, Telrad
Orion Dynamo Pro 12, Dew-Not
Have GLP and not afraid to use it!
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blb
sage
Reged: 11/25/05
Posts: 219
Loc: Piedmont NC
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Almost all amateurs use constellations while almost all professionals use computers and RA & Dec. Almost all amateurs look at the sky while almost all Professionals look at computers and photo's. Are not our publications for amateurs? We do not often read Professional journals! Why all the hoopla? Can we not make reference to the constellations for the amateurs? I don't know, you tell me.
--------------------
C-11, C-6, XT10i Dob, ETX125PE, TV102, & AT66
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David Knisely
Postmaster
Reged: 04/19/04
Posts: 8290
Loc: Beatrice, Nebraska
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Quote:
Almost all amateurs use constellations while almost all professionals use computers and RA & Dec. Almost all amateurs look at the sky while almost all Professionals look at computers and photo's. Are not our publications for amateurs? We do not often read Professional journals! Why all the hoopla? Can we not make reference to the constellations for the amateurs? I don't know, you tell me.
No, many amateurs use R.A. and Dec. If I am commanding my NexStar to slew to some object, I usually input either the catalog number of the object or its coordinates, not the constellation it is in. That having been said, the constellations do provide a sort of "identity" to the various objects within their borders. It is a little like saying a person lives in a particular city, even though their street address or latitude and longitude are not precisely specified. For that reason, I don't feel that there is anything "obsolete" about using constellations is various observing guides or lists. They are a useful way of getting a rough handle on where an object is. Clear skies to you.
--------------------
David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
Prairie Astronomy Club
http://www.prairieastronomyclub.org
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
Almost all amateurs use constellations while almost all professionals use computers and RA & Dec. Almost all amateurs look at the sky while almost all Professionals look at computers and photo's.
Boy, I sure don't agree with that dichotomy! I know *quite* a lot of amateurs who primarily look at computers and photos. There's a real tension at my astronomy club between the strictly visual observers, who consider any hint of light to be a major problem, and the astro-imagers, who really don't understand at an intuitive level why people complain about their bright computer screens.
As I said in an earlier note in this thread, I fear that in this age of Go To, many novice and intermediate amateurs know and use *neither* constellations *nor* celestial coordinates.
But beyond a certain level, all amateurs are quite familiar with both. Constellations are too ubiquitous to ignore, and celestial coordinates are absolutely essential once you move beyond the well-known warhorse objects.
--------------------
Tony Flanders
First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.
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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1075
Loc: Suburban Maryland
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Tony,
Quote:
Boy, I sure don't agree with that dichotomy! I know *quite* a lot of amateurs who primarily look at computers and photos. There's a real tension at my astronomy club between the strictly visual observers, who consider any hint of light to be a major problem, and the astro-imagers, who really don't understand at an intuitive level why people complain about their bright computer screens.
I certainly agree with that observation. I've experienced that tension myself at my usual dark site. Several times recently I have been there with my family, a couple other visual amateurs, and a couple astro-imagers. We visual folk call each other over to our own scopes now and then to look at an object. That's all good, no problem. But then when the AP guys ask us to come over to look at the Ring, for instance, it's not to look at it in the eyepiece. They want us to stare at an image on a computer screen with bright white light glaring in our eyes! They have absolutely no regard for a visual astronomer's dark-adaped eyes! It's as if the idea never crossed their minds at all. In the first place, when I'm at a dark site, I really don't want to stare at a digital image of a celestial object, I want to look at the object! I can look at a picture later when the AP guy uploads it to the internet. It does not interest me at all when I'm trying to see the object with my own eyes through my own scope. I can look at a photo anytime. (You may have guessed I have absolutely zero interest in astrophotography.)
Clear Skies Free From AP Light,
Mike
.... going back on topic
--------------------
Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
Barska XWA 10x50, 8x40
OptiView LPR 10x50
Const View 2.3x40
BV-125C
CG5, 2 drv / CG4, 2 drv, wood legs, ScopeStuff saddle / CG3, 1 drv
SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
QuikFinder, Telrad
Orion Dynamo Pro 12, Dew-Not
Have GLP and not afraid to use it!
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