C/2019 Y4 ATLAS in Ursa Major February 15, 2020 UTC
I could enjoy imaging of the comet through Saturday night.
The comet was drifting fast toward north northwest in Ursa Major. Whitish coma was round and bright. Whitish dust tail was short toward southwest. Greenish ion coma was faint, and the diameter was around 8 minutes at the night. North is up, and east is to the left.
The comet is expected to be bright, around magnitude 5 in May, 2020, though it comes too near to Sun, and we can not see it then.
Sun Distance: 2.228 AU
Earth Distance: 1.400 AU
equipment: Takahashi FSQ130ED and Canon EOS R-sp4II, modified by Seo-san on Vixen AXD equatorial mount, autoguided with Fujinon 1:2.8/75mm C-Mount Lens, Pentax x2 Extender, Starlight Xpress Superstar Autoguider, GPUSB, and PHD2 Guiding with comet tracking on
exposure: 7 times x 15 minutes, 5 x 4 min, and 5 x 1 minute at ISO 3,200 and f/5.0
The first exposure started at 13:30:22 February 15, 2020UTC. Shorter exposure frames were taken after moonrise.
site: 1,549m above sea level at lat. 35 48 51 North and long. 138 39 16 East in Yanagidaiwa Makioka Yamanasi 山梨県牧丘柳平
SQM-L was 21.42 toward the imaging field at the night.