The Crescent Nebula (also known as NGC 6888, Caldwell 27, and Sh2-105) is an emission nebula about 5000 light years away. It's formed by a fast stellar wind colliding with and energizing a slower stellar wind, both caused by the nearby Wolf-Rayet star WR 136. This collision creates a shell and two shock waves, one moving outward and the other moving inward.

Technical Information       
Date:                       August, 2014
Location:                 Green Valley, Arizona
Telescope:              Takahashi FSQ-106EDX
Camera:                  SBIG STT-8300M
Filters:                     Astrodon Gen 2
Mount:                     AstroPhysics 1200
Exposure:                HaRGB = 12:1:1:1 hours, all unbinned
Software:                 Acquisition: Maxim DL 5, TheSkyX, Pinpoint, CCD Commander
                                Processing: CCDStack, PhotoShop CS6 with various plugins

Crescent Nebula (NGC 6888)