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Hi everyone, I'm resurrecting this thread to say I now have some doubt about what I saw, and whether it was the nebula itself. I had another view last night that repeated what I saw before.

Appearance was a small gray "nebulosity" similar to a small galaxy with no core and no embedded stars. The Meade Narrowband filter did not help, in fact wiped it out.

However, looking more closely at many photos, there are four closely spaced stars with some relatively bright nebulosity at that location.

So now I wonder if I just saw the effects of the 4 stars? Or was it indeed nebulosity?


I marked up a DSS photo, it doesn't show the 4 stars, but does mark the spot. Mods, hope it is OK to use DSS photos.

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I think you saw it. I have seen it in my 10 inch as an irregular glow with two involved stars somewhat separated and one having a little more nebulosity around it than the other. I had the most luck with the nebula using the Lumicon Deep-sky filter, as the UHC seemed to help only very slightly over no filter. Just as a note, the "Cave Nebula" is Sh2-155, and while it is the 9th object in Moore's list, it should really not be given a "Caldwell number", as that is not an official astronomical catalog designation. Clear skies to you.

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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info

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About the questions raised in this thread on posting images, please read this sticky.

Let's get back to C9 now

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No, let's please get back to "the Cave Nebula" a.k.a. Sh2-155 or LBN 529, etc. "C9" is not really a standard designation in scientific astronomical databases. Clear skies to you.

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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info

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Due to the multitude of amateur astronomy media that does recognize and promote the C designations I may or may not use the reference at any future opportunity. Thanks in advance for any necessary flexibility in the matter.

In fact, the C9 designation seems particularly apt to its target mnemonic (C Nine/Cave Nebula). Heck, the thing even looks like a C.


Saber Does The Stars at
www.astronomyblogs.com/member/saberscorpx/

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The letter "C" is used in at least 13 different identifier abbreviations for astronomical objects, although it is most commonly used for the Catalogue of open cluster data, 1st edition, Lynga, Lund Observatory. 1987: Catalogue of Open Cluster Data, 5th edition, Lynga, Lund Observatory.:

http://vizier.u-strasbg.fr/cgi-bin/Dic-Simbad

Amateur astronomy is a hobby that is firmly based on the science of astronomy. Publications intended for amateur consumption are not the source of authority on this issue. The scientific community is. Letter/numbers should not be assigned to objects which are already officially recognized in designations from any of the standard scientific catalogs unless a new catalog is generated from the scientific research of a given scientist or group of scientists. This includes assigning numbers for the list created by Patrick Moore. If one wishes to be understood in amateur astronomy, it would be best if standard terminology is used. Clear skies to you.

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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info

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Patrick Moore seems to take the most abuse for this (C #'s), but I would like to point out that O'Meara's "Hidden Treasure's" book uses HT #'s and Levy's book uses L #'s.

I thoroughly understand the argument of proper catalog numbers, but when one is working on the Astronomical League's Caldwell observers award, it is easier to communicate with another individual who is also working on that list or has previously completed that list using C #'s. I for one, don't immediately recognise NGC #'s or C #'s without looking them up.

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I didn't find it easier at all when I did the Messier Objects more than 30 years ago, as all required reference to standard star charts and some of them required the use of a larger numerical designation on an atlas to locate them. Indeed, one early atlas (the early editions of Norton's atlas), had the original Herschel numbers instead of the more standard NGC/IC designators, and that actually made it harder to find the location of the target. Most print atlases use the Messier, NGC, IC, and perhaps one or two other lables which are from accepted scientific catalogs, so there is little need to introduce another one. Off the top of my head, I still can only identify maybe half of the Messier objects just by their M-numbers, so the argument about being easier just doesn't hold water. With the Herschel 400 or the Herschel II objects, the NGC numbers are used, and many of these numbers are quite commonly known among amateurs. I probably know at least a couple of dozen more prominent objects by their NGC numbers, but there are others who observe Deep-sky who know a lot more. Once a person becomes familiar with them, they are just as easy to communicate by their NGC designation as with some other non-standard one that just happens to contain fewer digits. Again, don't be surprised if, when you say, "I found Caldwell ###", someone else says, "Huh??". Clear skies to you.

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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info

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I personally have no problem with using either designation.

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Nor does our Terms of Service. CN members who wish to refer to objects by their designation on the Caldwell list should feel free to do so. (Official designations should be included, of course, as a courtesy to members not familiar with the Caldwell list.)

However, the TOS does forbid thread hijacking, which has unfortunately taken place here. From this point on, please return to the discussion of observations of the Cave Nebula.

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Tom W.

SVP8 'She turned me into a 3-legged Newt' EQ
Ralph, the All-Purpose 102mm Refractor
Under the Desert Stars New Entry

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