Messier 79 — Globular Cluster in Lepus

M79 is a globular cluster located about 41,000 light-years from Earth in the constellation Lepus, the Hare. It shines at magnitude 8.6 and spans about 118 light-years in diameter. What makes M79 unusual is its location in the sky — it lies in the opposite direction from the galactic center, far from where most globular clusters are found. This peculiar position has led astronomers to propose that M79 was not originally a Milky Way cluster but was captured from the Canis Major Dwarf Galaxy, a small galaxy currently being cannibalized by our own. The cluster has a concentration class V and contains several hundred thousand stars, many of them ancient red giants and horizontal branch stars typical of old stellar populations estimated at 11.7 billion years.

Located about 4 degrees south-southwest of the star Beta Leporis. M79 is easy to find by star-hopping from Alpha and Beta Leporis. In binoculars it appears as a fuzzy star. A 4-inch telescope at 100x shows a bright, condensed core with a granular halo. An 8-inch telescope begins to resolve individual stars around the edges, while the core remains a dense, blazing knot. Best observed from December through February when Lepus is highest — this is an excellent winter globular cluster, providing a welcome change from the summer globular cluster season. From mid-northern latitudes, it reaches a reasonable altitude for observing.

Discovered by Pierre Mechain on October 26, 1780, and cataloged by Messier on December 17, 1780. Messier described it as 'a nebula without a star, situated below the Hare.' William Herschel was the first to resolve it into stars. Its unusual position far from the galactic center puzzled astronomers for centuries. In 2003, studies of the Canis Major Dwarf Galaxy suggested that M79, along with several other outer-halo globular clusters, was likely captured from this dwarf galaxy as it was tidally disrupted by the Milky Way.