Messier 3 in Canes Venatici

Messier 3 in Canes Venatici, a photo by watchingthesky on Flickr.

Via Flickr:
M3 is a bright globular cluster. It has perhaps as many as 300 known variable stars, most of which are RR Lyrae stars. It has one lone W Virginis variable which is a type of Cepheid. The RR Lyrae stars are between 15th and 16th magnitudes whereas the W Virginis variable is between 12th and 13th magnitudes. For this image it measured 12.9V. It's too close to the core in this image to mark.