C/2012 S1 ISON with FSQ-106ED October 16, 2013UTC
Tail length was about 20 arcminutes at the night. North is up.
The length was about 4 arcminutes on September 16, 2013UTC. It got longer by 5 times in a month.
This 1,395 x 970 - pixel frame is cropped of full 5,634 x 3,753 - pixel frame. If I use a scope with focal length about 2.1m, 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 at the center of the condensation of the coma
exposure: 2 times 1,020 seconds at ISO 800 and f/5.0
The first exposure started at 18:56:02UTC and the last at 19:13:11UTC on October 16, 2013
site: 717m above sea level at lat. 35 50 03 N. and long. 138 18 00 E. in Hakushu, Yamanashi 山梨県北杜市白州
Ambient temperature was around 5 degrees Celsius, and SQM-L read as 21.07 at the best.
Here is a view of the site taken while this exposure for 17 minutes.