Deep Sky
M3
NGC 5272

Constellation: Canes Venatici
Globular Cluster
This globular was discovered by our man Charles Messier on 3 May 1764.  By 1784, the optics had  improved to the point that Bill Herschel knew it was a bunch of stars in 1784. 
This particular cluster is known to contain some 500,000 stars with a large population (274) of variable stars.  In fact, as late as 2004 astronomers were still adding to the number of variables stars to this bad boy. 
According to Wikipedia, M3 considered one of the finest examples of globular clusters in the northern Hemisphere, second only to M13.  Not too bad for ‘hood’ some 33,900 light-years away from us.  Astronomers gage this group of stars to be some 8 billion years old.

8 images stacked
20 sec ea
Date: 03-12-13