Messier 3 (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,^[8] 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.
https://en.m.wikipedia.org/wiki/Messier_3