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C/2012 S1 ISON with RH200f3 October 5, 2013UTC | by hirocun
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C/2012 S1 ISON with RH200f3 October 5, 2013UTC

The green halo got stronger, and the tail got longer, about 9 arcminutes. The length got longer by about 2 times in recent 19 days. I feel that the green halo is wider in northern side as in September 26. North is up.


Reaching the orbit radius of Mars, "frost line," the comet got activated much in the short period. The comet was drifting rapidly toward the left, toward the Sun at the night, 53 days before the perihelion.


Here is a frame taken in September 16, 2013.


We had experienced poor weather for more than a week in Tokyo, and the weather forecast was tragic widely for the new moon weekend except in the north end part of our country. I flew to Asahikawa with my middle-weight equipment in Saturday afternoon. Cloud looked thick in the airport. I drove north four hours and a half and reached the north end area of our country. It was cloudy, when I arrived at the site in the ranch in cape Soya, but it got clear gradually from the north just as the weather forecast. I could see Mars on a test frame taken at 16:41 October 5, 2013UTC, 1:41am on October 6, 2013 in JST.


It was a perfect and sleepy weekend for me.


This 1,096 x 802 - pixel frame is cropped of full 5,634 x 3,753 - pixel frame. If I use a scope with focal length about 3m, I may be able to take a frame of this scale without cropping.


equipment: Officina Stellare Riccardi-Hondars Astrograph D=200mm f/3.0 "Veloce," optical designed by Massimo Riccardi and Canon EOS 5Dmk2-sp2, modified by Seo-san on Takahashi EM-200 temma 2 Jr. equatorial mount, autoguided with hiro-design simple off-axis guider, Starlightxpress Lodestar Autoguider, and PHD guiding


exposure: 7 times 8 minutes at ISO 1,600 and f/3.0

The first exposure started at 17:59:00UTC and the last one started at 18:47:54UTC, ten minutes before the beginning of twilight on October 5, 2013.


site: 74m above sea level at lat. 45 29 15 N. and long. 141 56 27 E. in Cape Soya, Hokkaido, Japan

SQM-L read as 21.49 at the highest. Ambient temperature was around 12 degrees Celsius, 54 degrees Fahrenheit.

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Taken on October 5, 2013