Coma Cluster - Abell 1656

I got a wide field image of the Coma cluster. From this perspective it looks like a star cluster (almost) - except some of the stars look fuzzy. This is a 4 degree field. Image and exposure / processing details are at:

http://www.jthommes.com/Astro/DSLR/ComaCluster.htm

Scope - Zenithstar 66 APO
Camera - Canon 350D (Baader ACF modified) no external filters
Mount - Celestron CG5 GOTO
Guiding - Homemade 180 mm FL optic, Vesta 690, K3CCDTools

I like the crop version. Just need more time... Any idea of the sensitivity ratio between your DSLR and your other "astro" cameras?

Charlie

Nice wide field Jim.

At that scale it does look a bit like an open cluster.

Jason

Charlie, Jason,
Thanks for the comments.

Charles Hakes said:

I like the crop version. Just need more time... Any idea of the sensitivity ratio between your DSLR and your other "astro" cameras?

Charlie

I don't have any quantitative comparison just yet. I can say that the DSLR (on ISO800) is noticeably less sensative than my Art285 camera (like an ATIK16HR - Sony CCD ICX285). I would guess that I need to expose 2x to 3x longer for similar S/N and even that is going to have diminishing returns given the CMOS sensor in not cooled and is generally noisier and is 12 bit.