M12 (NGC 6218) is a Shapley-Sawyer class IX (http://en.wikipedia.org/wiki/Shapley%E2%80%93Sawyer_Concentration_Class) globular cluster located approximately 15,700 light-years away in Ophiuchus.
Luminance – 24x600s – 240 minutes – binned 1x1
RGB – 17:18:17x300s – 85:90:85 minutes each – binned 2x2
500 minutes total exposure – 8 hours 20 minutes
Imaged over five nights in March, 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/33609550126/sizes/l