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View Full Version here: : Comet Holmes enormous and tenuous


tornado33
29-12-2007, 01:34 AM
Hi all
Used the clear sky and period before moonrise to image Comet Holmes. Its now too faint for me to see visually, so took test images till I found it. All I could see was initially the central condensation and the inner coma. I was also unavoiadbly shooting through powerlines, hence some unevenness I could not get rid of completely. Star Atlas Pro indicated it is moving through a fairly rich field of galaxies, brighter members appear above the comet.

5x5 mins ISO200. Modded 350D. UV/IR filter Baader MPCC coma corrector. 6inch f3.6 Meade Cometracker Schmidt Newtonian. Hand guided.
Well I can definately say this is the "biggest" comet I have ever imaged, the coma takes up so much of the image, using the 10 inch scope would be pointless. Its definately well past its best though, rather low surface brightness now.
Scott

iceman
29-12-2007, 06:40 AM
Wow, it's huge! What's the diameter in arcseconds of the longest axis in your image?

Well done!

tornado33
29-12-2007, 08:33 AM
Hi, the FOV is 140 x 93 arc mins, so yes its a biggie now. I would have thought that in fading it would just get smaller as the coma dissipates, I wouldnt have thought it would keep growing in size like that.
Heres a Star Atlas pro screenshot with the FOV at 3 degrees, the rectangle re[resents the actual image size. The orientation may no match the actual image though.

Im pretty sure the 2 brighter galaxies near top are NGC 1161 and NGC 1160

A fainter one shining dimly through the coma would be UGC02468, (mag 13.4)
Scott

h0ughy
29-12-2007, 09:16 AM
fantastic scott thats awesome- that would be 200mm lens material

[1ponders]
29-12-2007, 09:57 AM
Nice shot Scott. :thumbsup: Hopefully if today stays clear I might actually unpack my gear and have a go tonight.

I got my first view in a couple of weeks last night and it looked pretty awesome. Still naked eye for me :D and looked great in the 10X50s. It is huge!!

davidpretorius
29-12-2007, 10:35 AM
wow, neveer seen anything like that before

thanks scott

Rob_K
29-12-2007, 02:51 PM
Very nice Scott - great to see it with that amount of detail! :thumbsup:

Cheers -

beren
29-12-2007, 05:06 PM
Congrats Scott fine capture :thumbsup: