Sharpless 166 (LBN 566 and others) is a faint HII region located approximately 7,700 light-years away in Cassiopeia.
Ha – 26x1800s – 780 minutes – binned 1x1
RGB – 8x300s – 40 minutes each – binned 2x2
900 minutes total exposure – 15 hours
Imaged over 11 nights from November, 2019 through January, 2021 from Dark Sky New Mexico at Rancho Hidalgo (Animas, New Mexico) with a SBIG STF-8300M on an Astro-Tech AT12RCT at f/8 2432mm.
HaRGB - https://www.flickr.com/photos/dcrowson/50987006156/sizes/l/