NGC 6633 (Mellote 201, Collinder 380 and others) is an open cluster of around 30 stars located approximately 1,000 light-years away in Ophiuchus.
Luminance – 12x600s – 120 minutes – binned 1x1
RGB – 8x300s – 40 minutes each – binned 2x2
240 minutes total exposure – 4 hours
Imaged from Dardenne Prairie, Missouri (a red zone) on May 6th and June 10th and 11th, 2016 with a SBIG ST-8300M on an Astro-Tech AT90DT at f/6.7 603mm.
LRGB - https://www.flickr.com/photos/dcrowson/27038662834/sizes/l