Crescent Nebula
Appearance
The Crescent Nebula (NGC 6888) is in the constellation Cygnus. The nebula is 4,700 light years from Sol. There's a central massive Wolf-Rayet star (WR 136) that shines by spraying gasses of its outer layers into space at 2,000-3,000 km/s. WR 136 will eventually end in a supernova explosion.