Messier 72
Messier 72 is a globular cluster in the Aquarius constellation discovered by French astronomer Pierre Méchain on August 29, 1780. French astronomer Charles Messier looked for it on the following October 4, and included it in his catalog. Both decided that it was a faint nebula rather than a cluster. With a larger instrument, British astronomer John Herschel called it a bright "cluster of stars of a round figure". American astronomer Harlow Shapley noted a similarity to Messier 4 and Messier 12.
This cluster is visible as a faint nebula in a telescope with a aperture. the surrounding field stars become visible at, while is sufficient to resolve the cluster with an angular diameter of 2.5′. At the core is resolved in a 1.25′ diameter, showing a broad spread with darker regions to the south and east.
Based upon a 2011 census of variable stars, Messier 72 is located at a distance of from the Sun. It has an estimated combined mass equal to 168,000 times the mass of the Sun and is around 9.5 billion years old. The core region has a density of stars that is radiating 2.26 times the luminosity of the Sun per cubic parsec. There are 43 identified variable stars in the cluster.
