Swan Nebula (M17) Imaged by Chris Thayer

M17, the Swan Nebula (also designated NGC 6618) is an emission nebula (HII region) in the constellation of Sagittarius.  The radiation of a cluster of stars embedded in nebula is exciting the gass and causing the emission.  It is roughly 40 light years in diameter and is  over 5,000 ly away.   Its mass is estimated to be 800 solar masses.

It was discovered by Philippe Loys de Ceseaux in 1745 and catalogued by Charles Messier in 1764.  

Lookup M17 on SEDS

Swan Nebula – click to enlarge

Imaged using an ED80 and DSI3 mono CCD, guided using a Meade DSI3c / LX200GPS 10″

Exposure details: 12 frames x 30sec using Ha Filter