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C/2012 S1 ISON with GSO 10"RCf/8 September 26, 2013UTC | by hirocun
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C/2012 S1 ISON with GSO 10"RCf/8 September 26, 2013UTC

The comet was already in Leo. Green halo was visible there again. North is up.

 

Weather forecast got better, and I could not wait till better night. I drove two hours from home and tried imaging of the comet. Moon was in the sky, and clouds came frequently. I could not autoguide the mount at the night, because I forgot a small piece of ring for guide camera. The focal length of the scope was 2m, and I could not make exposure beyond 30 seconds.

 

This 2,693 x 1,863 - pixel frame is cropped of full 5,634 x 3,753 - pixel frame. If I use a scope with focal length 4m, I may be able to take a frame of this scale without cropping.

 

equipment: GSO 10-inch RCCF f/8 with TS 2.5" field flattener, TS 2.5" OAG, and EOS 5Dmk2-sp2, modified by Seo-san on Losmandy G11 equatorial mount without autoguiding

 

exposure: 30 seconds at ISO 6,400, 55 frames out of 78 were used for this quick processing.

First exposure started at 18:18:24 September 26, 2013UTC

 

processing: frame drifted quickly, and ordinary registration of frames was impossible. I tried TRANS2 command of IRIS at the concentration of the coma, but it was not accurate enough for this bad set of frames to utilize all. I utilized 55 frames out of all 78 frames this time. Result is this frame with ugly registration. I will try TRANS command and register one by one later.

 

site: 1,330m above sea level at lat. 36 26 38 N. and long. 138 32 14 E. in Asama, Gunma

 

Here is a revised version with better registration.

www.flickr.com/photos/hiroc/9999259885/

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Taken on September 26, 2013