M15 (NGC 7078) is a Shapley-Sawyer class IV (http://en.wikipedia.org/wiki/Shapley%E2%80%93Sawyer_Concentration_Class) globular cluster located approximately 33,000 light-years away in Pegasus. With over 100,000 stars, M15 shines at a bright 6.2 magnitude.
Luminance – 24x600s – 240 minutes – binned 1x1
RGB – 8x300s – 40 minutes each – binned 2x2
360 minutes total exposure – 6 hours
Imaged October 14th and 15th, 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/38607881726/sizes/l
See my wider image here - - https://www.flickr.com/photos/dcrowson/20692459280/sizes/l.