NGC 246 (Caldwell 56, PK 118-74 1, Skull Nebula and numerous other designations) is a large, bright planetary nebula located approximately 1,550 light-years away in Cetus.
Luminance – 24x600s – 240 minutes – binned 1x1
RGB – 8x300s – 40 minutes each – binned 2x2
360 minutes total exposure – 6 hours
Imaged November 9th, 10th, 11th and 12th, 2017 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/24520779908/sizes/l