LBN 159 consists of all of the nebulosity in this image. Within it, Sharpless 100 (Sh2-100, NGC 6857, LBN 161) is the brightest knot of nebulosity above center. Sharpless 99 (Sh2-99, LBN 160) is the other bright knot to the right of Sh2-100.
Ha – 13x1800s – 390 minutes – binned 1x1
RGB – 8x300s – 40 minutes each – binned 2x2
510 minutes total exposure – 8 hours 30 minutes
Imaged from Dardenne Prairie, Missouri on July 29th and August 19th, 2015 with a SBIG ST-8300M on an Astro-Tech AT90EDT at f/6.7 603mm.
HaRGB - https://www.flickr.com/photos/dcrowson/20769548500/sizes/l