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Old 22-04-2009, 04:01 PM
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ngcles
The Observologist

ngcles is offline
 
Join Date: Dec 2006
Location: Billimari, NSW Central West
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Hi Beefking,

Quote:
Originally Posted by beefking View Post

... Encouraged by that victory, I thought I'd have a go at NGC 2818 - it looked more remote from bright stars so I assumed it would be harder to find. It's a pretty cool object - a cluster and planetary similar to M46, but the cluster and planetary are much closer in size, and the planetary did not have a well defined edge. It's an interesting object and I recommend it.

M83 - After that win, I thought I'd have a go at M83, which has always looked so far away from handy sign posts that it would be kind of impossible. It wasn't and I was rewarded with a large, round soft glow with a stellar centre. There seemed to be hints of more detail just out of reach, but with the amount of stray light flying around... well, I think it will be worth finding from a dark site.

this star-hopping thing, it's not so hard after all
Interesting report -- thanks for letting us all know how you went.

NGC 2818 is a wonderful PNe -- one of my summer/autumn favourites that rewards both a dark site and really good seeing.

First, this is how it looked in my old 10" in 1996:

x138 21' TF. Mag 8.2 Size 8'. Quite a small cluster which is no more than 10' diameter. The 4 brightest *s seem to mark boundaries, and a mag 11 * in the centre. scattering of maybe 50 *s mag 11.5 to threshold and milkiness in the centre. Mod range in brightness, More faint *s in the S end. On the outer halo in NW corner is NGC 2818A, and associated PNe.NGC 2818A Mag 11.8 Size 84" Easily visible at x86 without filtration. sort of "U" shaped and open to the NE. Roudish, unevenly lit. S side is distinctly brightest. Bright spot or stellaring there. Dark area (ie inside the "U", intrudes from the NE toward centre. A very pleasing object. No central * is evident. Diffuse edges.

and here is an observation I made of it with my 18" in 2006 from Bargo under a "nearly-dark" sky with good seeing:

NGC 2818A Planetary Nebula
RA: 09h 16m 01.5s Dec: -36 37' 37"
Mag: 13.0 (P) Size: 93.0"x55.0" Class: 3b
Mag C. Star: 19.4 R.V.: ---

12mm, 9mm & 7mm Naglers, x185, x247 x317, (Unfiltered, UHC & OIII)

This is the first time I've seen this PNe in this aperture and it didn't disappoint -- a very interesting and unusual PNe. The brighter areas look like a pair of longish butterfly wings without the butterfly body in the centre -- longish opposing mirrored triangles with the long axis in PA 90. Each long triangle is about 30" long and 10" wide at the widest and the N one is slightly the weaker in brightness and definition. The short sides of the triangle are the best defined but the two long Hypotenuse much less defined on their edges. An area around this is very weakly nebulous out to 60" diameter. Moderately bright. Good response to OIII and UHC. Some bluish/smoky bluish colouration Best at x247 with 9mm T1 Nagler.

where it showed much of the detail visible in this image here:

http://www.capella-observatory.com/I...s/NGC2818A.htm


12" will show undoubted spiral structure in M83 -- keep trying. I've seen the arms in 6" at a top-notch site and others with better eyes have done it in yet smaller 'scopes.

Re star-hopping -- yep it is a skill. Like riding a bike it takes a while to master but is a skill that is never forgotten.


Best,

Les D
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