M103 (NGC 581) is a magnitude 7.4 open cluster of 25 to 172 stars (depending on the source) located approximately 8.500 light-years away in Cassiopeia. The bright star at the bottom right is magnitude 2.62 Ruchbah (HIP6686).
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 September 21st, 2015 with a SBIG ST-8300M on an Astro-Tech AT90DT at f/6.7 603mm.
LRGB - https://www.flickr.com/photos/dcrowson/21633883716/sizes/l