M81 (NGC 3031, UGC 5318, Bode’s Galaxy and others) large spiral galaxy located approximately 11.8 million light-years away in Ursa Major.
Holmberg IX (UGC 5336 and others) is the faint dwarf irregular galaxy to the left of M81.
Luminance – 24x600s – 240 minutes – binned 1x1
RGB – 8x300s – 40 minutes each – binned 2x2
360 minutes total exposure – 6 hours
Imaged April 2nd, 2017 and January 12th and 13th, 2018 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.
LRGB - https://www.flickr.com/photos/dcrowson/39001691054/sizes/l