Messier 72
Messier 72 is a globular cluster in the south west of the very mildly southern constellation of Aquarius.
Observational history and guide
M72 was discovered by astronomer Pierre Méchain in 1780. His countryman Charles Messier looked for it 36 days later, and included it in his catalog. Both opted for the then-dominant of the competing terms for such objects, considering it a faint nebula rather than a cluster. With a larger instrument, astronomer John Herschel called it a bright "cluster of stars of a round figure". Astronomer Harlow Shapley noted a similarity to Messier 4 and 12.It is visible in a good night sky as a faint nebula in a telescope with a aperture. The surrounding field stars become visible from a -aperture device. One of will allow measurement of an angular diameter of 2.5 [arcminutes|]. At the core is clear: its 1.25 [arcminutes|] diameter, meaning a broad spread; and small parts scarcer in stars to the south and east.