Messier 13 is the Great Globular Cluster in the constellation of Hercules. It is one of the largest and most beautiful globular clusters visible from the northern hemisphere.

At magnitude 5.8, M13 is visible to the keen unaided eye at a dark-sky observing site. It is located 25,000 light-years away. It has an apparent angular diameter of 15 to 20 arcminutes, depending on the size of the telescope used to observe it. This corresponds to a real size of 115 light-years. It contains hundreds of thousands of stars.

M13 was discovered in 1714 by Edmond Halley and catalogued by Charles Messier in 1764.

Galaxy NGC 6207 can be seen at the lower left. Another small faint galaxy, IC 4617, can also be seen to the left of center of the photograph.

North is to the left in the above image.

M13 Catalogs: M13, NGC 6205 Common Name: Hercules Globular Cluster Object Type: Globular Cluster Magnitude: 5.8v Size: 20' Constellation: Hercules Image Field Centered At: RA: 16h 42m 00s Dec: +36° 32' 55"