M4 (NGC 6121)
Messier M4 (NGC 6121) is a globular cluster located in the constellation Scorpius, in the Galactic Center of the Milky Way Galaxy. in the Local Group of galaxies.
Messier M4 is best viewed during mid-summer, is magnitude 5.9*, and can be viewed with naked eye (just barely). It is 26.3' 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.
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