M53

Globular star cluster M53 is one of the more outlying globulars, being about 60,000 light years away from the Galactic center, and almost the same distance (about 58,000 light years) from our Solar system. At this distance, its apparent angular diameter of 13' corresponds to a linear diameter of roughly 220 light years. It is rapidly approaching us at a velocity of about 100 km/sec. M53 has a bright compact central nucleus of about 2' in diameter, although its stars are not very concentrated toward the center when compared to other globulars, and a gradually decreasing density profile to the outer edges. As in all globular clusters, the stars of M53 are apparently "metal-poor", which means that they contain only small amounts of elements heavier than helium. The cluster has been found to contain a relatively large number (47) of RR Lyrae variables.

Image taken May 11, 2007, with the 402 camera and the Meade focal reducer. 10 minutes exposure.