M17 (NGC 6618) - Omega Nebula
Messier 17 (NGC 6618), also known as the Omega Nebula, is a diffuse nebula located in the constellation Sagittarius, in the Sagittarius Arm of the Milky Way Galaxy in the Local Group of galaxies. M17 is 5,500 light years away from Earth.
M17 is best viewed during late summer, is magnitude 6, and can be viewed with naked eye (barely). M17 is 11' in apparent size. For reference, the full moon is 30' (arc minutes) in size.
* The naked eye can see up to magnitude 8 objects under ideal dark sky conditions.