Globular Cluster M10 (also known as Messier Object 10, Messier 10, M10, or NGC 6254) is a globular cluster in the Ophiuchus constellation. It was discovered by Charles Messier in 1764. A globular cluster is a spherical bundle of stars (star cluster) that orbits a galaxy as a satellite. ... Ophiuchus (known as the serpent holder) is one of the 88 constellations, and was also one of the 48 listed by Ptolemy. ... Charles Messier Charles Messier (June 26, 1730 – (April 12, ]) was a French astronomer who in 1774 published a catalogue of 45 deep sky objects such as nebulae and star clusters. ... 1764 was a leap year starting on Sunday (see link for calendar). ...