The star cluster M3 is between Arcturus Bootes (α Bootis) and double stars, the brightest of hunting dogs (Cor Caroli). The apparent magnitude of the cluster M3 is 6.3, just above the limit of visibility with the naked eye. In binoculars you will see a whitish spot and diffuse. If most of the cluster stars are older than 10 billion years, a large number of stars are blue, so young, a few hundred million years.
The object was discovered by Charles Messier in 1764 but William Herschel who around 1784 realized it was a cluster of stars. M3 contains a considerable number of stars, about half a million, most stars are old and red.
Light takes about 35,000 years to reach us from M3, which spans about 150 light-years.
This image is a composite of 30 x 120 seconds and 30 x 30 seconds processed in Photoshop CS5.
Takahashi Astrograph and QHY10 CCD......Lights, Darks, Flats, and Bias frames calibrated in Nebulosity V2.5