Messier 2 — Globular Cluster in Aquarius

M2 is one of the largest and richest globular clusters in the Milky Way, located about 37,500 light-years from Earth in the constellation Aquarius. It contains roughly 150,000 stars packed into a sphere about 175 light-years in diameter. The cluster is extremely old, estimated at 13 billion years, making it nearly as old as the universe itself. Its stars are tightly concentrated toward the center, giving it a Shapley-Sawyer concentration class II rating — among the most compact globulars known.

Located about 5 degrees north of the star Beta Aquarii. Under very dark skies it is just visible to the naked eye at magnitude 6.3. Binoculars show a fuzzy, round glow. A 4-inch telescope reveals a bright core surrounded by a grainy halo. Apertures of 8 inches and above begin to resolve individual stars across the cluster, especially away from the dense core. Best observed from August through October when Aquarius is well-placed in the evening sky.

Discovered by Jean-Dominique Maraldi in 1746 while observing a comet. Charles Messier independently found it and cataloged it in 1760, describing it as a 'nebula without stars.' William Herschel was the first to resolve it into individual stars in 1783 using his large reflecting telescope.