Right Ascension	13 : 42.2 (h:m)
Declination	+28 : 23 (deg:m)
Distance	30.6 (kly)
Visual Brightness	6.2 (mag)
Apparent Dimension	16.2 (arc min)
Discovered by	Charles Messier May 3rd, 1764

This cluster was the first "original" discovery by Charles Messier when he logged it on May 3rd, 1764. At that time it was the 67th deep sky object ever observed by human eyes (and apparatus), although at that time, it was only the 62nd known nebulous object. It was also apparently the discovery of this object which eventually caused Charles Messier to start a systematical search for these comet resembling objects, and not just catalog chance findings as in the previous cases M1 and M2, as is demonstrated by the fact that in 1764, he found and measured all the objects M3-M40.

M3 is one of the most outstanding globular clusters, containing an estimated half million stars! It is extremely rich in variable stars: According to B. Madore (in Hanes/Madore, Globular Clusters, 1978), 212 variables have been found, 186 periods determined, more than in every other globular cluster in our Milky Way galaxy (and thus the most ever observed); at least 170 RR Lyrae variables were discovered.

"Nebula discovered between Bootes and one of Hevelius's Hunting Dogs. It does not contain any stars." Charles Messier Charles Messier from his Catalogue ( Again showing his scope was unable to resolve a Globular..)

Main information courtesy S.E.D.S.