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C/2012 S1 ISON with FSQ-106ED October 13, 2013UTC v.2 | by hirocun
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C/2012 S1 ISON with FSQ-106ED October 13, 2013UTC v.2

I tried comet guiding again. Tail length was about 13 arcminutes at the night. North is up.


I've added almost all data taken at the night.


This 1,236 x 833- pixel frame is cropped of full 5,634 x 3,753 - pixel frame. If I use a scope with focal length about 2.4m, I may be able to take a frame of this scale without cropping.


equipment: FSQ-106ED and EOS 5Dmk2-sp2, modified by Seo-san on EM-200 temma 2 jr. autoguided with FS-60C, Lodestar Autoguider, and PHD guiding


exposure: 3 times x 1,200 seconds, 2 x 900 sec, 2 x 240 sec, and 8 x 60 seconds at ISO 800 and f/5.0


The first exposure started at 17:56:58UTC and the last at 19:46:50UTC on October 13, 2013. Twilight began at 19:25UTC in the morning. Autoguiding at the center of the condensation of the coma got stable at 17:48UTC or 2:48JST, when the object was at 13.8 degrees above horizon. Autoguiding was continuously stable till 19:53UTC or 4:53JST, 28 minutes after the beginning of twilight, though I did not combine the first 6 60 second-exposure frames and the last four 60 second-exposure frames. Frames were blurred for atmospheric turbulence at the beginning and the last hour frames were already bluish too much.


site: 1,556m above sea level at lat. 36 41 32 N. and long. 138 39 19 E. near Lake Nozori, Gunma 群馬県野反湖

Ambient temperature was around 2 degrees Celsius, and SQM-L read as 21.49 at the best.

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Taken on October 13, 2013