drshr
professor emeritus
Reged: 06/09/08
Posts: 674
Loc: Darwin, Australia
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Just wondering if anyone has tips for seeing this elusive object. Visual not AP.
It doesn't even get a mention in Burnham,s Cat.
I have tried UHC and broardband filters with little joy. 
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Doc
14" F5 DOB.
APM 8" F6 Achro.
APM 105mm F6.2 CF APO.
120/F8.3
150/F5
80/F6.25ED
25x100 Binos.
To affect the quality of the day, that is the highest of arts.
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Tony Flanders
Post Laureate
Reged: 05/18/06
Posts: 3469
Loc: Cambridge, MA, USA
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Quote:
Just wondering if anyone has tips for seeing this elusive object. Visual not AP.
It doesn't even get a mention in Burnham,s Cat.
I have tried UHC and broardband filters with little joy.
Mmm, it's one thing to view it here in the Northern Hemisphere, where it's directly overhead. It must be tough indeed from Australia.
I found it most contrasty with an H-Beta filter, but liked the view best with my UHC. A broadband filter certainly isn't going to help any!
Other than that -- what can I say? Dark skies are essential, aperture certainly helps. It's quite large, with no sharp edges, so best viewed at low to medium power. Then work the area over with averted vision. It took me several sessions before I was sure I'd seen 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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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1275
Loc: Ottawa, Ontario, Canada
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Last night we had a quite transparent air mass drift over eastern Ontario, following the passage of a cold front. It was among the best of nights we can experience at our latitudes. Using my home-made right angle bino in 7X50 mode, *unfiltered*, I did get a hint of its presence at the head of the cometary dark nebula, B168.
This is one of those objects which really benefits from a dark sky. And that means it should be *at least* 20-30 degrees above the horizon as seen from a site unafflicted by light pollution.
As to Burnham's lists, I look at them as antiquated. They were born of a time when such modern contrivances as narrow band filters for visual observation were hardly conceived of, let alone commercially available.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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Jeff Morgan
Carpal Tunnel
Reged: 09/28/03
Posts: 1987
Loc: Prescott, AZ
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The only time I was ever sure I caught the Cocoon on the first try was with two eyes - a 4" f/10 achromat with a binoviewer. Mono vision, it is always seems to be hard and subtle.
I'll put it on the top of the list for my next session with the Oberwerk BT-100-45's.
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Jeff Morgan
Prescott, AZ
Wile E. Coyote School of Telescope Making
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drshr
professor emeritus
Reged: 06/09/08
Posts: 674
Loc: Darwin, Australia
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Interesting answers.
Thank you gentlemen.
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Doc
14" F5 DOB.
APM 8" F6 Achro.
APM 105mm F6.2 CF APO.
120/F8.3
150/F5
80/F6.25ED
25x100 Binos.
To affect the quality of the day, that is the highest of arts.
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peter k
super member
Reged: 02/03/07
Posts: 172
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Glenn, that's really impressive!
The Cocoon has been very frustrating for me. I've tried for it several times with smaller refractors and my 8" SCT, always from pretty dark skies (SQM 21.0-21.5), all to no avail. Finally got it in my 10" dob with UHC filter (per David Knisely's recommendation) and a 27 Panoptic. So moderate to large aperture, UHC (or maybe H-beta, per David K.), large exit pupil, and dark skies worked for me. Good luck!
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BillFerris
Carpal Tunnel
Reged: 07/17/04
Posts: 2910
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The Cocoon is only visible under pristine dark & transparent skies. Darwin's southerly latitude will, therefore, be a real challenge as the Cocoon climbs to about 30 degrees above the horizon and the air's still pretty mucky at that altitude. But keep trying. You never know when you'll get that perfect night.
Bill in Flag
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Grand Canyon Adventure
Lowering the Threshold
18" Obsession
4.5" Meade 4500
10x50 Swift Audubon
Cosmic Voyage
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Hrundi
Pooh-Bah
Reged: 02/06/08
Posts: 1237
Loc: Estonia
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Is it possible to see this one unfiltered?
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dpwoos
sage
Reged: 10/18/06
Posts: 218
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I have tried to observe the Cocoon Nebula several times in the past, and without success. However, these posts inspired me to try again, and I just got in after my first successful observation. I used our 10" f/6 homemade dob, a 30mm Paragon eyepiece (50x), and a Lumicon 2" UHC filter. Finding the dark nebula that leads to it is easy, and the journey down this dark road is itself worth the trip. I especially enjoy a fishhook-shaped asterism that borders the dark nebula. Even with the filter the nebula was faint. Next time I am going to try my club's 2" H-Beta filter.
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David Knisely
Postmaster
Reged: 04/19/04
Posts: 8280
Loc: Beatrice, Nebraska
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Quote:
Is it possible to see this one unfiltered?
Yes, from a dark sky with six to 10 inch apertures, the Cocoon nebula can be seen as a dim roughly circular smudge of light with a few involved stars. A Narrow-band filter (Lumicon UHC, DGM NPB, Orion Ultrablock, etc), will help it somewhat over non-filter use. The H-Beta filter will help it a bit more by giving it somewhat more contrast, although in the H-Beta, the nebula is a bit fainter than in the narrow-band filters. In particular, filters help with the interior dark lane-like features that stand out better than without filtration. 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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Hrundi
Pooh-Bah
Reged: 02/06/08
Posts: 1237
Loc: Estonia
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So a 12" is already too much?  And I don't have any filters either, so maybe I should stay away from these 'ultrawide' nebulae 
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MikeRatcliff
Pooh-Bah
Reged: 06/12/04
Posts: 1329
Loc: Redlands, CA
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Ha, no it's visible in a 16" without a filter also. But it takes a dark sky and it's not "bright" by any means. As someone said already, it is made easily visible with the H-beta filter, but the overall view is better aesthetically without such a strong filter.
Mike
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16" f/4.9 dob, 1.25" Paracorr, 24 TV Widefield, 18 Circle T ortho, 13 Nagler T6, 12.5 UO ortho,
9 Circle T ortho, 2x TV Barlow 1.25"
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Jeff Young
Post Laureate
Reged: 08/04/05
Posts: 4116
Loc: Ireland
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I have two observations logged:
Quote:
IC5146 Cocoon Nebula 9/7/2007 22:25 UT; Pickering 7, NELM 6, SQM 20.7
16" SCT @ 124X, UHC
Without filtration it's more noticable as a dark nebula which knocks out most of the background stars in an otherwise quite populous neighborhood. Must be a lot of Hbeta in there as the OIII is worse than no filter at all, and the UHC is of modest help.
Still, not much to see visually.
Quote:
IC5146 Cocoon Nebula 10/12/2006 21:00 UT; Pickering 6, NELM 5.5, SQM 20.8
16" SCT @ 108X, UHC
Dark sections actually easier to find than bright ones, which are nearly invisible without filtration. OIII provides very little help, but UHC and averted vision bring out the mottling and dark spaces around the stars. Still pretty subtle, though.
Listed with an integrated magnitude of 7.2. Probably should have tried the FC-100....
So it's visible from rural-suburban-transition skies with 16" both filterted and unfiltered, although in neither case is it much to look at. I now have an Hbeta, but I didn't at the time of either of those observations....
-- Jeff.
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Nikon 18x70s / UA Millennium Colorado:
Solarscope SF70 / TV Pronto / AP400QMD Coronado SolarMax40 DS / Bogen 055+3130
APM MC1610 / Tak FC-100 / AP1200GTO Tak Mewlon 250 / AP600EGTO
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Dave Mitsky
Postmaster
Reged: 04/08/02
Posts: 10499
Loc: PA, USA, Planet Earth
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I've seen the Cocoon Nebula through a very large Dob at a very dark site. Even with 32 inches of aperture, it was not very impressive.
Dave Mitsky
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Chance favors the prepared mind.
De gustibus non est disputandum.
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18UCinVA
super member
Reged: 10/24/08
Posts: 150
Loc: Virginia
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I never saw it in a 12". Finally in an 18", without a filter. The cluster is pretty poor also. The long thin Barnard 168 is the best feature of The Coccon.
The Pac-Man NGC 281 in Cas was easy in an 80mm the first time I looked.
I find the easier nebulas to be more rewarding. Sure I love the challenge, but I tend to fog up ep's. Everything looks nebulous then.
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Ray
18 UC
Celestron 32, 24, and 20mm Erfle's
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drshr
professor emeritus
Reged: 06/09/08
Posts: 674
Loc: Darwin, Australia
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Strange that it is No 19 in the Caldwell list!!!
Mr Moore must have great eyesight through that monocle! 
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Doc
14" F5 DOB.
APM 8" F6 Achro.
APM 105mm F6.2 CF APO.
120/F8.3
150/F5
80/F6.25ED
25x100 Binos.
To affect the quality of the day, that is the highest of arts.
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David Knisely
Postmaster
Reged: 04/19/04
Posts: 8280
Loc: Beatrice, Nebraska
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Quote:
Strange that it is No 19 in the Caldwell list!!!
Mr Moore must have great eyesight through that monocle!
The Caldwell numbers are arranged in order of decreasing declination, so the numbers are not a "ranking", but merely a positional notation. 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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sgottlieb
sage
Reged: 07/22/07
Posts: 339
Loc: SF Bay area
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Quote:
The long thin Barnard 168 is the best feature of The Coccon.
and a great binocular object in a dark sky. Looks like a narrow black river extending from M39 to the Cocoon.
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Steve Gottlieb
18" f/4.3 Starmaster
Adventures In Deep Space
7500+ NGC/IC Visual Descriptions
NGC/IC Project
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obrazell
member
Reged: 04/03/05
Posts: 56
Loc: United Kingdom
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I don't think Mr Moore observed any of these objects. The list was taken from photographs. I don't think he would ever get dark adapted after looking at the moon :-)
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