Observer's guide
About Hercules Globular Cluster
Hercules Globular Cluster (M13) is catalogued as a globular cluster in Hercules. Its J2000 position is RA 16:41:41.63, Dec +36:27:40.7, corresponding to 250.4235 degrees RA and 36.4613 degrees Dec. The local catalogue places it about 22,800 light-years away. Its referenced angular extent is approximately 33 by 33 arcminutes.
Observing tips
StarWatchr rates this as a very easy target at magnitude 5.8. It is associated with summer observing, with midnight placement typically strongest around May. From 52 degrees north its theoretical meridian altitude is about 74.5 degrees; local horizons and the live altitude chart determine the practical window.
Its brightness makes it a practical binocular or small-telescope candidate when it is well above the horizon.
What to expect
The SIMBAD classification for the matched source is GlC. A published radial velocity value is -244.4 km/s. The SIMBAD record currently connects it to 2311 bibliographic references.
Its roughly 33 arcminute span suits a medium field of view. Use the listed 33 by 33 arcminute extent to check framing, and treat catalogue magnitude as integrated brightness rather than a direct measure of visual contrast.