M5 (NGC 5904)

M5 (NGC 5094)

The globular cluster Messier 5.
Image: Sonoita Observatories.

M5 (NGC 5904) is a bright, compact globular cluster in the constellation Serpens, 8° southwest of alpha Serpentis. Under very good seeing conditions, M5 can just be glimpsed with the naked eye. Binoculars reveal it as a fuzzy patch. It was first seen by Gottfried Kirch and his wife Maria Margarethe in 1702, and found independently by Charles Messier in 1764. William Herschel was the first to resolve it into stars.

M5 shows a marked ellipticity and is one of the oldest globular clusters in the Milky Way Galaxy with an estimated age of 13 billion years. It may contain as many as half a million stars.


visual magnitude 5.6
angular size 23'
linear diameter 165 light-years (50 pc)
distance 24,500 light-years (7,500 pc)
position R.A. 15h 18m 34s,
Dec. +02° 04' 58"
other designations GCl 34, C 1516+022