M28 (NGC 6626) is a Shapley-Sawyer class IV (http://en.wikipedia.org/wiki/Shapley%E2%80%93Sawyer_Concentration_Class) globular cluster located approximately 19,500 light-years away in Sagittarius.
Barnard 309 is the dark nebula near the top center of the image.
Luminance – 12x600s – 120 minutes – binned 1x1
RGB – 8x300s – 40 minutes each – binned 2x2
240 minutes total exposure – 4 hours
Imaged on June 16th and July 12th, 2020 at the Danville Conservation Area (New Florence, Missouri) with a SBIG ST-8300M on an Astro-Tech AT90EDT at f/6.7 603mm.
LRGB - https://www.flickr.com/photos/dcrowson/50109275456/sizes/l/