M20 (NGC 6514) - Trifid Nebula
Messier 20 (NGC 6514), also known as the Trifid Nebula, is a nebula w/cluster located in the constellation Sagittarius, in the Sagittarius Arm of the Milky Way Galaxy in the Local Group of galaxies.
M20 is best viewed during late summer, is magnitude 5.0*, and can be viewed with naked eye (barely). It is 28' in 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.