MikeRatcliff
Pooh-Bah
Reged: 06/12/04
Posts: 1107
Loc: Redlands, CA
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Finally, after several attempts
From Joshua Tree National Park this Saturday night. The darkness there is rated blue on the light pollution maps, although I was looking in a favorable direction to the northeast away from the light domes.
Saw a small area of nebulosity. Noted the area and double checked against some photos to confirm. The appearance was more like a small galaxy you might see in a galaxy cluster like the Coma Cluster, or an HII region of M33 but dimmer. Nothing at all like the photographs of course.
Mike R.
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16" f/4.9 dob
Tele Vue Plossls 32,25,20,15,11
13 Nagler T6
10.5 Pentax XL
Brandon 32, 16
12.5 UO ortho, 9 Circle T ortho
2x TV Barlow
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deepsky
sage
Reged: 12/04/05
Posts: 210
Loc: oregon
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Congrats Mike!
I Found Sharpless 2-155 to be the most difficult visual confirmation.
Did you use your 16"? I needed to "borrow" a 16" in order to confirm the sighting a few years ago at the Table Mountain Star Party in Washington State.
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jim jackson
Astroleague Observer Award junkie
Messier Club-Honorary
Lunar Club
Binocular Messier Club
Double Star Club
Herschel 400 Club
Urban Observing Club
Deep Sky Binocular Club
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Southern Sky Binocular Club
Southern Sky Telescopic Club
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MikeRatcliff
Pooh-Bah
Reged: 06/12/04
Posts: 1107
Loc: Redlands, CA
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Yes, the 16". Also with no nebula filter.
At around 2 a.m. in the morning my mind was a bit fuzzy. I forgot to check with a filter! And I didn't write down or remember which eyepiece. I think it was the 10.5mm Pentax XL (190x) that I was using most of the night.
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16" f/4.9 dob
Tele Vue Plossls 32,25,20,15,11
13 Nagler T6
10.5 Pentax XL
Brandon 32, 16
12.5 UO ortho, 9 Circle T ortho
2x TV Barlow
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tatarjj
scholastic sledgehammer
Reged: 04/20/04
Posts: 905
Loc: Auburn, AL
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That's an interesting observation Mike. I've only been able to detect a rather large (maybe 30', I don't remember) glow near the threshold (18" obsession). That is with UHC filtration, I think, but I don't have my notes with me. I never thought to look for any tiny, bright details. You suppose you detected a small reflection nebula around an embedded star?
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John T.
Auburn, AL
25" f/4.2 Dob
18" Obsession #701
4" Stellar Vue Achromat
8X56 Binos
Edited by tatarjj (06/20/07 01:08 PM)
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MikeRatcliff
Pooh-Bah
Reged: 06/12/04
Posts: 1107
Loc: Redlands, CA
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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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16" f/4.9 dob
Tele Vue Plossls 32,25,20,15,11
13 Nagler T6
10.5 Pentax XL
Brandon 32, 16
12.5 UO ortho, 9 Circle T ortho
2x TV Barlow
Edited by MikeRatcliff (07/26/08 03:27 PM)
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MikeRatcliff
Pooh-Bah
Reged: 06/12/04
Posts: 1107
Loc: Redlands, CA
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Here's a closeup
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16" f/4.9 dob
Tele Vue Plossls 32,25,20,15,11
13 Nagler T6
10.5 Pentax XL
Brandon 32, 16
12.5 UO ortho, 9 Circle T ortho
2x TV Barlow
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David Knisely
Postmaster
Reged: 04/19/04
Posts: 6777
Loc: Beatrice, Nebraska
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Quote:
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.
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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SaberScorpX
Post Laureate
Reged: 01/12/05
Posts: 4121
Loc: illinois, usa
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Congrats on C9, Mike. Tough target.
Your description sounds like a valid observation.
Saber Does The Stars at
www.astronomyblogs.com/member/saberscorpx/
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David Knisely
Postmaster
Reged: 04/19/04
Posts: 6777
Loc: Beatrice, Nebraska
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Sh2-155, A.K.A. "The Cave Nebula" also bears the designation LBN 537 (Lynds Catalog of Bright Nebulae). Clear skies to you.
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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
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GlennLeDrew
professor emeritus
Reged: 06/18/08
Posts: 617
Loc: Ottawa, Ontario, Canada
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The reason for the great difficulty in seeing Sh2-155 (the Cave) is that it's quite reddened by intervening dust. While I'm not certain, I am rather confident that there are no reflection components, or if there are, they're also significantly reddened so as to make visual observation problematic.
Why Mr. Moore included this challenging object defies any logic I can devise...
A more interesting (and at least easier) observation to be made is of the stellar association Cepheus OB3, to which the Cave is also associated.
Cep 3 is a fairly obvious enhancement of 6-9 mag. stars, 3.5 x 1.25 deg. in extent, oriented roughly NE-SW. The Cave lies at the SW end. The distance to Cep 3 is about 2,500 to 3,000 l-y.
The intervening dust renders many of the otherwise bluish O-type stars rather yellowish, and dims them by as much as a couple or even a few magnitudes. It's this extinction which subtracts much of the H-beta and O-III light of the associated nebulosity.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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tatarjj
scholastic sledgehammer
Reged: 04/20/04
Posts: 905
Loc: Auburn, AL
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Well, tight stars can often give the illusion of nebulosity, and the fact that a narrowband filter wiped it out doesn't help you much. My experiences with this nebula have always been that it's a rather largish object, the best visible portions being maybe 15'-30' across- I can't remember off the top of my head. I can't remember ever trying for the object WITHOUT a nebula filter. If you actually did see something it had to have been some reflection nebulosity, which might not necessarily count as seeing Sh2-155 itself. Just keep at it- Sh2-155 is faint, but it IS observable with a narrowband filter and decently large scope.
As for posting the POSS/DSS images, from my experience here, make sure you say explicitly where you got them and say it again and again every time you post a POSS image, otherwise the moderators may come down on you. It's not ok to just say they are from the POSS.
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John T.
Auburn, AL
25" f/4.2 Dob
18" Obsession #701
4" Stellar Vue Achromat
8X56 Binos
Edited by tatarjj (07/29/08 01:46 PM)
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Olivier Biot
Amused
Reged: 04/25/05
Posts: 14323
Loc: 51°N (Belgium)
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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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Tal-200K (#199) with JMI NGF-Mini2M focuser on GEM3 • Astro-Tech AT80ED on Orion Sirius EQ-G with EQDIR & home made wireless EQDIRECT • Celestron Regal LX 8x42 & 10x42 • Helios 15x70
ATM 14" f/5 (designing mirror cell and filter wheel/focuser) • ATM 10" f/6 Portable Truss (polishing) • ATM 10" f/25 Dall-Kirkham (primary: polishing, secondary: #120 grit)
AstroForecast
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MikeRatcliff
Pooh-Bah
Reged: 06/12/04
Posts: 1107
Loc: Redlands, CA
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For the record, the two images I posted earlier were from the Digital Sky Survey,
http://stdatu.stsci.edu/cgi-bin/dss_form
PS Simbad gives the wrong coordinates if you type "Cave Nebula". Apparently there is more than one.
It was too late to edit those posts directly.
Now back to Sh2-155 ... (don't call it C9!)
I did have another look the next night which was a better night for transparency, seeing, and thermal equilibrium of the mirror (meaning it stayed hot, never getting below about 85 degrees F, bad for me).
Pretty much the same view except the nebulosity was brighter, I could see a couple of star glints 10-20% of the time from the small nebulous area knot. The area does seem nebulous but too small to be the main nebula. UHC filter did hurt again.
I did see hints of larger nebulosity to the south of this knot (no filter), which would be in the right place. I need confirmation viewings, but this gives me some hope.
Thanks all,
Mike R
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16" f/4.9 dob
Tele Vue Plossls 32,25,20,15,11
13 Nagler T6
10.5 Pentax XL
Brandon 32, 16
12.5 UO ortho, 9 Circle T ortho
2x TV Barlow
Edited by MikeRatcliff (07/30/08 08:50 PM)
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David Knisely
Postmaster
Reged: 04/19/04
Posts: 6777
Loc: Beatrice, Nebraska
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Quote:
About the questions raised in this thread on posting images, please read this sticky.
Let's get back to C9 now
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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Olivier Biot
Amused
Reged: 04/25/05
Posts: 14323
Loc: 51°N (Belgium)
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Be my guest
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Tal-200K (#199) with JMI NGF-Mini2M focuser on GEM3 • Astro-Tech AT80ED on Orion Sirius EQ-G with EQDIR & home made wireless EQDIRECT • Celestron Regal LX 8x42 & 10x42 • Helios 15x70
ATM 14" f/5 (designing mirror cell and filter wheel/focuser) • ATM 10" f/6 Portable Truss (polishing) • ATM 10" f/25 Dall-Kirkham (primary: polishing, secondary: #120 grit)
AstroForecast
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SaberScorpX
Post Laureate
Reged: 01/12/05
Posts: 4121
Loc: illinois, usa
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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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David Knisely
Postmaster
Reged: 04/19/04
Posts: 6777
Loc: Beatrice, Nebraska
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Quote:
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/
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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SaberScorpX
Post Laureate
Reged: 01/12/05
Posts: 4121
Loc: illinois, usa
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Thanks for the input.
I'll probably still include a related scientific moniker for information's sake.
Saber
www.astronomyblogs.com/member/saberscorpx
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dlferree
super member
Reged: 06/20/06
Posts: 119
Loc: Rio Rico, Arizona
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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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Dave
DSH-10
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Dave Mitsky
Postmaster
Reged: 04/08/02
Posts: 6272
Loc: Pennsylvania, USA
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OTOH, neither of those books makes the mistake of promoting a personal list of favorite deep-sky objects, which anyone could make, as a legitimate astronomical catalog.
Dave Mitsky
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