Crescent Nebula
The Crescent Nebula (NGC 6888) is in the constellation Cygnus. The nebula is 4,700 light years from Sol. It was formed by the final phase of the central massive Wolf-Rayet star WR 136. It 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.