Asteria — interactive night sky map
Hercules Cluster (Messier 13) is a globular cluster in the constellation Hercules with an apparent magnitude of 5.8, spanning about 17 arcminutes. Under dark skies it can be spotted with the naked eye.
It is best placed in the evening sky around May. It is visible from the whole northern hemisphere and from southern latitudes down to about 54°S. It is circumpolar (never sets) north of latitude 54°N.