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Observing >> Deep Sky Observing

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azure1961p
Postmaster
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Reged: 01/17/09

Loc: USA
Re: More care with object names, please new [Re: kfiscus]
      #6106581 - 09/28/13 08:59 PM

A lot of folks today use their phones to post and the dinky little touchscreen pads so there is that. At any rate I can ignore a lot of typos for decent content.

Pete


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Lamb0
Carpal Tunnel
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Reged: 07/25/07

Loc: South Eastern(ish) Nebraska
Re: More care with object names, please new [Re: azure1961p]
      #6106924 - 09/29/13 03:43 AM

... but it's also fun when observing with a group to invent silly names for clusters, nebulae, galaxies, etc. - just so long as there's a valid designation for the logbook!

It would help if there were free spell checkers, dictionaries, and a worthwhile thesaurus for browsers that are better "guessers" for intent rather than just a "correct" spelling for any old word - but English, particularly the "American" conglomeration, is anything but "simple" - especially for those trying to read posts that suffer from loquacious verbosity!


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dan777
professor emeritus
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Reged: 11/16/07

Loc: Indiana
Re: More care with object names, please new [Re: kfiscus]
      #6107077 - 09/29/13 09:00 AM

Quote:

I'm pretty hung up on spelling errors in my OWN posts but just grin-and-bear-it with others'.



I get hung up with spelling errors particularly when they change (or at least confuse) the meaning of the sentence. Don't people proof read their material? Interestingly, I don't recollect spelling errors from you "senior posters"* who generally articulate your comments very well.

*senior posters = posters on this thread with 1000 or more posts

And of course, my comments don't apply to our non-English speaking friends. I admire these people for knowing more than one language.


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Kraus
Pooh-Bah


Reged: 03/10/12

Loc: Georgia.
Re: More care with object names, please new [Re: dan777]
      #6107321 - 09/29/13 11:49 AM

OK. So is it pronounced Betelgeuse or Betelgeuse?

I've heard both but I prefer the first.

The second pronunciation is as foolish as those who think they're cute by mispronouncing the seventh planet. I immediately discount them.

And...Pluto is the ninth planet. It has moons, thus it's a planet. I declare such.


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IVM
scholastic sledgehammer


Reged: 01/07/08

Loc: Western New York
Re: More care with object names, please new [Re: Kraus]
      #6107428 - 09/29/13 12:48 PM

I thank you all for your comments and for your attention to this little matter of our forum's appearance. And of course I did not mean for my OP to sound overbearing - only collegial.

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nytecam
Postmaster


Reged: 08/20/05

Loc: London UK
Re: More care with object names, please new [Re: kfiscus]
      #6107478 - 09/29/13 01:10 PM

Must be very cloudy in the States to use all this energy on this topic :-)

Patrick Moore's Caldwell Catalogue is the result of an invite by S&T editors but he was strictly a solar system observer with little interest in deep sky objects so it's surprising it's taken that seriously.


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IVM
scholastic sledgehammer


Reged: 01/07/08

Loc: Western New York
Re: More care with object names, please new [Re: nytecam]
      #6107528 - 09/29/13 01:29 PM

Maurice, the weather here is indeed so-so. I hope to have a good long session at a remote site in the middle of the week though. Since (I believe) there isn't much left to discuss about spelling, we can as well regard this thread now to be about Caldwell

First, I was surprised that the debate did not die down with Sir Patrick's departure. While he was one of us (in a broad, egalitarian sense ) I also could feel some resentment stirring deep down: why was he invited to publish a deep-sky list and I wasn't? Another smiley here would be unsightly but it is implied.

Second, in his foreword to O'Meara's "Caldwell Objects" book Moore stated that he had personally observed all of the objects on his list (before penning it, I believe he meant). My criteria may carry little weight, but even if that was all he observed of the deep sky it should qualify him as a deep-sky observer, considering all the visual toughies on the list and the fact that some real dedication is required to see them all given that it is an all-sky list.


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kfiscus
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Reged: 07/09/12

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Re: More care with object names, please new [Re: IVM]
      #6108285 - 09/29/13 09:57 PM

I didn't know the background of the Caldwell List. I knew Sir Patrick was a heavy hitter and prolific author. I have muttered (and posted) a few unkind words about his list and some of its entries. It IS a challenge and I do like the unique idea of having it declination/latitude-determined. All this being said, the list is firmly established (at least in the USA) and I am nearly done with the items within my reach. (I have 15 left of 76.)

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David Knisely
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Reged: 04/19/04

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Re: More care with object names, please new [Re: IVM]
      #6108528 - 09/30/13 12:56 AM

IVM wrote:

Quote:

First, I was surprised that the debate did not die down with Sir Patrick's departure. While he was one of us (in a broad, egalitarian sense ) I also could feel some resentment stirring deep down: why was he invited to publish a deep-sky list and I wasn't? Another smiley here would be unsightly but it is implied.




Other than adding an additional (and totally unnecessary) designator (the "C" numbers) onto objects which were already well know by other established scientific catalog numbers, the main problem with the Caldwells is that the list has a number of poorly-chosen objects on it. As a "follow-on" to the Messiers, it just isn't all that outstanding, which was a little surprising given Moore's reputation. Presumably, the Caldwell list was created hopefully to present the new observer with a number of good worthwhile objects that didn't make it into the Messiers. Before the Caldwell list was created, the next step after the Messiers for many amateurs was going after the lengthy and more challenging Herschel 400 listing (a list with a few problems of its own). While the Herschel 400 contains a lot of real "gems" of the deep-sky, it generally contains a lot more difficult objects to find and observe in modest telescopes than the Messiers, so some kind of intermediate listing would have been nice to have (a sort of "Herschel Lite" list). This, presumably, was at least part of the motivation behind the creation of the Caldwell list. However, the inclusion of some really marginal targets that can frustrate and discourage the amateur is questionable in any list presuming to contain good deep-sky targets. The only exception might be those lists which as a list are deliberately made difficult so that they *are* all intended as a complete challenge and nothing else.

The most difficult objects on the Caldwell list appear to have somewhat questionable observational value as "bright nebular objects omitted by Messier", as Moore puts it. The most common "objectionable" one appears to be the now infamous "Cave" Nebula Sh2-155, which can be quite challenging (and rather underwhelming visually), especially for those just coming off of completing the Messier observing program. If someone thinks that the Cave Nebula was difficult, they might need to try IC 1613 (the 51st object in Moore's Caldwell list). That one took me a while to see even in my 10 inch under dark clear skies. I found the location fairly quickly and easily, but I had to rock the scope and really study the area to detect the faint irregular "brightening of the sky background" that is that dim dwarf galaxy (surface brightness is only 15.9 mag/sq.arc-min.). For a list presumably of "bright nebular objects omitted by Messier", Sh2-155 and IC 1613 may be somewhat questionable entries.

There are a few other very challenging targets in the Caldwell list, such as the "Flaming Star" nebula IC 405 (the 31st object on the list). In modest apertures, it can be all but invisible without filters and can sometimes be tough even with filters. At a true dark-sky site in a wide-field moderate aperture instrument with the H-Beta filter, it isn't enormously difficult, but it still isn't exactly something to write home about. One would think that an experienced amateur astronomer could come up with a better object to put on the list than that one. Surprisingly, the Caldwell list excludes some rather obvious nebulae like the "Pac Man" Nebula NGC 281 in Cassiopeia, or "Thor's Helmet" NGC 2359 to name only two. If, for some unexplained reason, the list needed to include one or two more difficult objects, instead of the rather obscure "Cave" nebula, why not include something a lot more famous like the Horsehead Nebula (IC 434/B33) instead? For some unknown reason, the Horsehead didn't make the grade either.

In its coverage of galaxies, the Caldwell list also puts in a few real doozies like NGC 4236 (#3 in the list), a large elongated spiral that has an incredibly low surface brightness (15.0 mag/sq.arc-min). That one had to wait for the Astronomical League's Herschel II group of *challenging* objects for a place on a list of potential DSO targets. Similarly, the very dim large face-on spiral IC 342 is on the Caldwell list (#5), but again, there are a number of better targets which could have gone in its place. Indeed, IC 342 was so faint that it had to wait for the Index Catalog to be listed somewhere. The bright galaxy NGC 2903 in Leo would have made a really good entry (visible in binoculars), but curiously, it is missing from the Caldwells as well. This makes one really wonder about what exactly the criteria were for the selection of objects to go on the Caldwell list. To Moore's credit, he did extend the list into the southern skies to highlight some of the more interesting deep-sky wonders down there, but I suspect that, from the problems with the northern coverage, there could be a few strange object inclusion choices down there as well.

A list with many challenges is fine (try the Herschel II's if you want a challenge). However, such a list should be more consistent in its level of difficulty and its selection of objects. Indeed, while not listing some really good DSO targets and putting in some faint challenges, the Caldwell list abruptly goes to the other extreme by putting in two ridiculously-easy ones: the Hyades and the Coal Sack. It is almost as if this list's creator couldn't decide who the target user was supposed to be. The Messiers represent most of the easier DSO's and are generally for the newer amateur who is just getting into the hobby with modest aperture telescopes (a 3 inch will show all of them usually). The Herschel 400 is targeted for intermediate amateurs who already have some skills for finding and observing the Deep-sky (six to 10 inch apertures typically). The Herschel II is targeted for the experienced amateur as a true challenge to their finding and observing skills (10 inches of aperture and up). What is the Caldwell target? Beginner? Intermediate? Advanced? From the object selection, it is difficult to judge here. It is this strange inconsistency which tends to be somewhat bothersome to many amateurs who have gone through the structure of the Messier, Herschel 400, and Herschel II programs.

Does this mean that the Caldwell list is worthless? Of course not. Like many observing projects, its goal is to get you out with your scope to observe, and, if followed, it largely achieves that goal. It has a lot of interesting objects on its list, and is worth going over as a guide on what might be worth going after. However, it is important to understand why some amateurs may not appreciate it. Their reasons do, in my book, have at least some validity, as there are better lists which existed before the Caldwell one, and could serve the amateur as well or better. Clear skies to you.


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IVM
scholastic sledgehammer


Reged: 01/07/08

Loc: Western New York
Re: More care with object names, please [Re: David Knisely]
      #6108658 - 09/30/13 03:53 AM

Ken, the arrangement by declination (or reverse declination) may be unique among catalogs in use today. But in the 19th century James Dunlop's celebrated southern catalog was arranged by declination, and I believe Dunlop had predecessors in this - although I find myself unable to give another example at the moment and therefore may be wrong.

As always insightful notes on the lists, David. It was my impression that the original S&T publication was an example of heavy-handed editing, or (equally likely and essentially the same thing to say), Sir Patrick was not too attuned to the specifics of the invitation he received. It seems that S&T wanted an "apres-Messier" list, Moore produced what struck his fancy, and S&T published it as an "apres-Messier" list nonetheless. The hard facts are in Moore's foreword to O'Meara's book on the list. He wanted a diverse list with a) Messier-class non-Messier objects, b) objects that would challenge even big-telescope owners, and c) objects that globe-trotting astronomers would enjoy and that would encourage amateurs to travel. Pretty much his words but not verbatim of course.


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blb
Post Laureate


Reged: 11/25/05

Loc: Piedmont NC
Re: More care with object names, please new [Re: IVM]
      #6109052 - 09/30/13 10:57 AM

I for one have enjoyed the Caldwell list of objects for observing. But I do object to this list of already cataloged objects being called a catalog and would prefer that when talking about an object on the list that the standard reference designation for the object be used. Thats just so that everyone will know what is being talked about and there is no ambiguity on what is being discussed.

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Fuzzyguy
sage


Reged: 12/21/11

Loc: Colorado/Kansas
Re: More care with object names, please new [Re: IVM]
      #6109214 - 09/30/13 12:37 PM

Quote:

"apres-Messier" list




Excuse my ignorance, but please define. I'm not sure I understand what this phrase means even after searching for a definition. Thanks!

PS Glad this thread has morphed into something more appropriate to the forum than than its rather "snarky" (IMO) beginnings. I hope readers will not exit the forum based on one thread. Of all the great forums here, I enjoy this one the most for its friendly, informative non-judmental posters!


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David Knisely
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Reged: 04/19/04

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Re: More care with object names, please new [Re: Fuzzyguy]
      #6109338 - 09/30/13 02:06 PM

Quote:

Quote:

"apres-Messier" list




Excuse my ignorance, but please define. I'm not sure I understand what this phrase means even after searching for a definition. Thanks!

PS Glad this thread has morphed into something more appropriate to the forum than than its rather "snarky" (IMO) beginnings. I hope readers will not exit the forum based on one thread. Of all the great forums here, I enjoy this one the most for its friendly, informative non-judmental posters!




It basically means "after the Messier list", or as a follow-on to that list. As such, the Caldwell list is OK, but is less successful than it could have been (with a little "tweaking" done by some of the more prominent deep-sky observers). Clear skies to you.


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Fuzzyguy
sage


Reged: 12/21/11

Loc: Colorado/Kansas
Re: More care with object names, please new [Re: David Knisely]
      #6109349 - 09/30/13 02:19 PM

Thanks David!

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IVM
scholastic sledgehammer


Reged: 01/07/08

Loc: Western New York
Re: More care with object names, please new [Re: Fuzzyguy]
      #6109441 - 09/30/13 03:16 PM

Thanks, David.

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fred1871
professor emeritus


Reged: 03/22/09

Loc: Australia
Re: More care with object names, please new [Re: IVM]
      #6110452 - 10/01/13 01:05 AM

Quote:

Ken, the arrangement by declination (or reverse declination) may be unique among catalogs in use today. But in the 19th century James Dunlop's celebrated southern catalog was arranged by declination, and I believe Dunlop had predecessors in this - although I find myself unable to give another example at the moment and therefore may be wrong.





Back in James Dunlop's day, the use of "reverse Declination" was not unusual, because it derived from meridian circle work, where positions were listed as 'NPD' (North Polar Distance) - hence 10 degrees NPD would be Declination +80.

For Dunlop, working in the Southern Hemisphere, the corresponding measure is SPD, South Polar Distance, as used in his catalog of 1827.


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Gil V
sage


Reged: 09/09/12

Re: More care with object names, please new [Re: fred1871]
      #6111498 - 10/01/13 04:10 PM

David -

I noted with interest your magnitude/arc minute squared measurement.

Is that sort of information readily available? I find a magnitude alone isn't enough information, as the size of the object does correspond with the ability to detect it.

Thanks in advance


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David Knisely
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Reged: 04/19/04

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Re: More care with object names, please new [Re: Gil V]
      #6111546 - 10/01/13 04:42 PM

Quote:

David -

I noted with interest your magnitude/arc minute squared measurement.

Is that sort of information readily available? I find a magnitude alone isn't enough information, as the size of the object does correspond with the ability to detect it.

Thanks in advance




The surface brightness figures for at least some deep-sky objects (mostly galaxies) are available in the third volume of Uranometria 2000.0 (the Deep Sky Field Guide). They are also sometimes available in other printed works or some of the on-line catalogs and the more advanced observing software like MEGASTAR, or THE SKY. Some use the figure in magnitudes per square arc minute (MEGASTAR and Uranometria's Field Guide for example) while others use the magnitude per square arc second, so one has to be careful keeping those units straight between sources of information (add 8.89 to a magnitude per square arc minute figure to get magnitudes per square arc second). Like you, I find the surface brightness figures to be somewhat more valuable in gauging the visibility of galaxies than just the total integrated visual magnitude figure is. Clear skies to you.


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Dave MitskyModerator
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Re: More care with object names, please new [Re: Gil V]
      #6112401 - 10/02/13 02:19 AM

Surface brightness figures are included in the Night Sky Observer's Guide.

http://www.willbell.com/handbook/nitesky.htm

Surface brightness figures can also be found in some of Stephen O'Meara's books such as Deep-Sky Companions: The Messier Objects.

Dave Mitsky


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stevecoe
"Astronomical Tourist"
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Reged: 04/24/04

Loc: Arizona, USA
Re: More care with object names, please new [Re: Dave Mitsky]
      #6113576 - 10/02/13 05:09 PM

Dave, et al;

Those values are free in the SAC database.

www dot saguaroastro dot org

Look under downloads on the left side;
Steve Coe


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