The Great Hercules Cluster is a globular star cluster containing upwards of one million individual stars. Bound into tight orbits by their mutual gravitation for one another, the stars range in size and color from red giants to common yellow dwarves much like our Sun. As seen in this image, the more luminous members are typically red giants. Globular star clusters, in general, are considered some of the oldest objects in the Milky Way Galaxy, because they are composed mostly of older Population II stars. Such stars contain much lower levels of heavy elements than the Sun, which means that they were formed from the metal-poor material that was prevalent when our galaxy was in its infancy. Covering more than 20 arcminutes of sky, M 13 is often obvious to the unaided eye as a faint "fuzzy" object located within the keystone astrerism of the Hercules constellation. Also of note are the two background spiral galaxies NGC 6207 and IC 4617 located to the lower left in this image. They are of about 12th and 16th visual magnitudes, respectfully. Image taken with homemade 8-inch f/5.4 astrograph and SBIG STL-11000XM. LRGB image composed of 30 minutes each R,G,B and synthetic L channel. Click on the image above for the high resolution version.