M18 (NGC 6613)
Messier 18 (NGC 6613) is an open cluster located in the constellation Sagittarius, in the Sagittarius Arm of the Milky Way Galaxy in the Local Group of galaxies. M18 is 4,200 light years away from Earth.
M18 is best viewed during late summer, is magnitude 7.5, and can be viewed with binoculars. M18 is 10' 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.