Globular Cluster M 53

This is one of the most distant globular clusters—located about 58,000 light-years from Earth. The cluster contains a 33-millisecond pulsar in a binary system with an orbital period of 256 days, discovered in 1991. M53 is in the constellation Coma Berenices—a spring sky object easily spotted with binoculars or a telescope finder about one degree northeast of the faint α Comae Berenices. In a medium amateur telescope, this is one of the most distant Messier globular clusters and is barely resolved into individual stars, appearing as a small fuzzy ball with a fairly bright center and a gradual drop in brightness toward the edges. Starting with apertures of 250–300 mm, the halo begins to resolve into stars fainter than 13.5m. About 10 arcminutes south of M53, a pair of 9th-magnitude stars can be seen. One degree to the southeast (not in the frame) lies the faint globular cluster NGC 5053.