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Spot galaxies, nebulae, star clusters, and other objects outside of our solar system
Dumbell
Last post 09-08-2008 09:35 AM by astronig. 15 replies.
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DaveMitsky

- Joined on 07-25-2001
- Pennsylvania, USA
- Posts 6,184
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Under dark skies through a medium sized aperture, M27 is decidedly oval-shaped and somewhat resembles a fattened football, with an inner "apple core" center that is somewhat brighter. Several stars can be seen within the nebulosity.
A narrowband filter such as a Lumicon UHC or Orion UltraBlock or an O-III filter will enhance your views of the Dumbbell Nebula.
http://www.astrophoto.net/m27.html
Dave Mitsky
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chipdatajeffB

- Joined on 07-16-2002
- Dallas area, Texas
- Posts 7,258
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This object is fairly large and bright. Light pollution will prevent your seeing it from an urban or suburban site. An OIII filter will help with the LP issue, but I prefer to view it unfiltered. Of the three filters you mentioned, the OIII would be the most useful overall with an 11-inch SCT.
To my eye in a 6-inch scope at 50X it has an apple-core shape. An 11-inch scope should show a great deal more of its outer layers and it should look almost round, unless you have the power cranked up too high. An 11-inch SCT has some serious focal length, so the 40mm eyepiece might be too much. You want a wide-field eyepiece if you use more than 100X on it.
If you were using a C-11, you'd have been at 70X but would have had a restricted field of view.
One way to be sure you identified it correctly would be to use your finder scope. In that part of the sky, it's the only faint fuzzy you'll be able to see in a typical finder scope, but will require an LP-free sky.
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leo731

- Joined on 10-19-2005
- Posts 1,448
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With my 6" SCT at 66x with a narrow band LP filter it reminds me of a brick. In my 8" Newt at 48x with the filter it looks more like the apple core shape with a faint halo.
Without the filter it is nearly impossible to see from my LP site as it remains very faint and fuzzy as it blends in with the background.
L
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Bill Weir

- Joined on 11-24-2003
- Metchosin (Victoria), Canada
- Posts 1,218
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If you are sure you were in the general vicinity to begin with, then I'm sure you found it. I can't think of any large object in the general vicinity that aren't cluster. It seems like light pollution is the culprit. From a reasonably dark location the shape is distinct in even my little 80mm refractor. With my 6" dob the outer halo is clearly seen. With the 12.5" it always makes me think of some sort of alien lizard eyeball. With the 25" it's difficult to find words to describe it.
Bill
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Arawn75

- Joined on 09-16-2007
- Joliet, Illinois
- Posts 327
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Would it be correct to say that I would not have seen any color though? The sky had a bit of light pollution in it. I would say it was oval in shape as well, just a lack of any color. Thanks for the great information.
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chipdatajeffB

- Joined on 07-16-2002
- Dallas area, Texas
- Posts 7,258
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No color. You need lots of aperture to show color in planetary nebulae.
With enough aperture, though, they can be the most colorful direct-view objects, since they are relatively bright for DSOs.
I often get the use of 20" and larger dobs, up to 30" ... but even the 30" fails to show color on most DSOs. Your mileage may vary as observers have different levels of color sensitivity under low light.
When get up in the range of two meters' aperture, though, you'll see color quite well in many planetaries. I haven't observed with the telescopes at Mt. Wilson, though I know someone who has. He says many planetaries show good color in the 60-inch.
I have observed with the 82-inch Struve telescope at McDonald Observatory and planetaries are absolutely vivid in that scope on a good night.
The least expensive way to discern color in typical amateur scope apertures is to image with a CCD camera. It's not inexpensive, just lots less expensive than moving to a large enough scope to show color visually.
Lack of color doesn't mean lack of detail, however, as the above Replies show. You can discern shape, and some amount of detail pretty readily on The Dumbbell. Some of the other planetaries within reach of 11-inch apertures show even more detail, or interesting shapes. Try The Owl, or The Eskimo, for example.
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ngc2438

- Joined on 04-25-2008
- Thailand
- Posts 121
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chipdatajeffB:You need lots of aperture to show color in planetary nebulae
I might be lucky with my eyesight but, I have conflicting experience ref planetaries and color. Some PNs are bright and have such a high surface brightness that they show color even in 8-10 inch scopes. I'd like to give you a few sample PNs that should clearly show color in an 11-inch. I have included only brighter objects with pronounced color that I have observed myself. Some show color in an 8 inch scope. Clear Skies!
NGC 1535 (in Eridanus, 9.6 mag, diameter 20", blue)
NGC 2440 (in Puppis, 9.1 mag, 50x20", intense blue)
NGC 3242 (in Hydra, 8.6 mag, 40", grey-blue)
NGC 3918 (in Centaurus, 8 mag, 12", bright light blue)
NGC 6818 (in Saggitarius, 9.3 mag, 17", blue)
NGC 6826 (in Cygnus, 8.8 mag, 25", blue)
NGC 7027 (in Cygnus, 8.4 mag, 20", greenish-blue)
NGC 7662 (in Andromeda, 9 mag, 17", intense greenish-blue)
Campbell's Star PK 64+5.1 (in Cygnus, 10 mag, 8", red !)
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chipdatajeffB

- Joined on 07-16-2002
- Dallas area, Texas
- Posts 7,258
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Nice list. I'll check them out!
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DaveMitsky

- Joined on 07-25-2001
- Pennsylvania, USA
- Posts 6,184
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Jeff,
I've detected color in a number of bright planetary nebulae with my 4" refractor and other observers have reported doing so as well. While I've never seen any color in M27, even through scopes in the 30-inch range, there have been reports that it can be done.
http://cs.astronomy.com/asycs/forums/p/26926/348548.aspx#348548
Coincidentally, there's a great shot of the Dumbbell Nebula on APOD today.
Dave Mitsky
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Arawn75

- Joined on 09-16-2007
- Joliet, Illinois
- Posts 327
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Thank you for the replies. It is the first planetary I have looked at so I was not sure what to expect. I look forward to seeing more so thanks for the list I will check those out.
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DaveMitsky

- Joined on 07-25-2001
- Pennsylvania, USA
- Posts 6,184
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You should be able to see M27 through your finder scope, assuming that you have one, or a binocular unless your skies are terribly light polluted.
Dave Mitsky
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chipdatajeffB

- Joined on 07-16-2002
- Dallas area, Texas
- Posts 7,258
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Well, I guess it's time to get my eyes checked again ... sigh.
As a guess, I'd say I've observed about 40 planetary nebulae ... something like that. I've seldom confirmed color in apertures under about 20 inches. Certainly I have not seen color as depicted in photographs of these wildly colorful objects.
Most of the color I've seen in apertures in that range are gray-green or light blue. I can see light blue in the Blue Snowball in apertures around 10 inches ... I don't know that I've tried it in smaller apertures, but will have to check my observing notes on that score.
I haven't undertaken these observations as a specific project, but it's a good idea for one. Perhaps this would be fun?
I have observed several very colorful PN using the 82" Struve reflector at McDonald Observatory. Many of them look very much like their photographs with this much aperture, displaying not only blues but also yellow and gold.
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Oliver Tunnah

- Joined on 12-05-2005
- Bristol UK
- Posts 876
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DaveMitsky: Ha, that was taken with FTN by a professional. Even though his was a 2x mosaic his narrowband image is not to dissimilar to mine. (Also taken with FTN) Just he had it more red. My Ha and Hb blended to make Purple. 
I have only seen M27 as a grey fluff from a dark site. However my scope was quite small.
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Wolf359
- Joined on 07-15-2008
- Canfield, Ohio
- Posts 6
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Sounds like you found it. It is kind of faint (like a out of focus cotton ball) until your eye adjusts. I use a Lumicon Deep Sky filter. This makes nebula (and others) stand out from the background (increases contrast). I've tried other nebular and LPR filters, but the Lumicon works best for me. The Meade nebular filter is pretty close to the Lumicon, and a bit less pricey. Bill
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astronig

- Joined on 11-06-2007
- M.V. ,Ca.
- Posts 1,664
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In my 5 inch it is more like a bow tie or apple core or hourglass . In the 8 inch the outer reaches become apparent in that the circular shape is visable . I have never seen it as an oval . You should be able to get great views at 100x or even a little more . My suggestion would be a Narrowband Neb filter as opposed to the OIII filter , but that would be personal pref . Try both . Dave
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