- M 56 (NGC 6779)
M 56 is a (visually) small globular cluster almost lost in the stream of the Summer Milky Way along the east border of the constellation Lyra. Its small size (7 arc-min diameter) and low brightness (visual magnitude 8.4) renders the cluster as a small softly glowing ball in small telescopes. A telescope of 6 to 8 inches aperture is needed to fully resolve it into its component stars. M 56 is only about a third of the size of M 13 (200,000 Solar masses) with a physical diameter of around 55 LY. It lies at a distance of around 27,390 LY. Over 250 million years, its eccentric orbit takes it out to a maximum of 40,000 LY from the galactic core, but its closest approach takes it to only a few thousand LY from the galactic core. The brightest stars in the cluster reach a visual magnitude of 13.
M 56 was discovered by Charles Messier on the 19th of March, 1779, while he was observing a comet previously discovered by Bode. He described it as a "nebula without star." Five years later, John Herschel was able to resolve the cluster into individual stars.
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