Messier 3 (also known as M3 or NGC 5272) is a globular cluster of stars in the northern constellation of Canes Venatici. It was discovered by Charles Messier on May 3, 1764, and resolved into stars by William Herschel around 1784. Since then, it has become one of the best-studied globular clusters. Identification of the cluster's unusually large variable star population was begun in 1913 by American astronomer Solon Irving Bailey and new variable members continue to be identified up through 2004.
The brightest and largest globular cluster in the Milky Way, containing as many as 10 million stars
The globular cluster is found in the constellation Centaurus, in the Southern Hemisphere.
It is 16,000 light-years from earth.