SUNSET: 
0
Photographer:
Jon Greif
Location of Photo:
La Jolla, CA, USA
Date/Time of photo:
July 18-19, 2022, from 9 pm to 3 am PDT
Equipment:
Takahashi FSQ-85ED with 1.01 Flattener, ZWO ASI533MC Pro imaging camera, Optolong L-Pro filter, ZWO 30 mm guide scope, ZWO ASI290MM mini guide camera, Rainbow Astro RST-135 mount, ZWO ASIAIR Plus controller and capture software, and Pixinsight 1.8.9 processing software on a Macbook Pro.
Description:
This is comet C/2017 K2 (PANSTARRS), which was closest to Earth on July 14, 2022, although, it’s not actually particularly close at 172 million miles away. Astronomers first spotted this comet in 2017 using the Pan-STARRS survey instrument in Hawaii. At the time, they said it was the farthest active inbound comet they’d yet seen. It was between the orbits of Saturn and Uranus when they first saw it. We imaged the comet last night with 5+ hours of exposure time through our 85 mm Takahashi refractor. Skies were clear, but sky quality still poor -- after all, we live in a big bright city, and we were just days away from the biggest, brightest supermoon of the year. I measured the Sky Quality Index at 18.34, which corresponds with a 7 on the Bortle Scale (https://en.wikipedia.org/wiki/Bortle_scale), which is exactly what you expect for fringe of a big city -- Sky Quality of 21 or higher would be nice, and help to see the tail of this comet. We hope to get out into some dark skies in the next few weeks, and re-image comet C/2017 K2 (PANSTARRS), including its tail.
