Messier 11 — Open Cluster in Scutum

M11, the Wild Duck Cluster, is one of the richest and most compact open clusters known, located about 6,200 light-years from Earth in the constellation Scutum. It contains roughly 2,900 stars, of which about 500 are brighter than magnitude 14. The cluster spans about 25 light-years across. At an estimated age of 220 million years, its brightest stars are blue-white main sequence stars of spectral types B8 to A0. A single bright yellow star of magnitude 8 stands at the apex of a V-shaped pattern of stars that inspired its common name.

Located at the northern end of the Scutum Star Cloud, one of the richest areas of the Milky Way. At magnitude 5.8, M11 is visible to the naked eye as a hazy spot. Binoculars show a bright, compact glow. A 4-inch telescope at 75-100x reveals a spectacular dense cloud of faint stars with the bright yellow star at the front. An 8-inch telescope resolves hundreds of stars against the rich Milky Way background. One of the most rewarding open clusters for any aperture. Best observed from July through September.

Discovered by Gottfried Kirch in 1681 at the Berlin Observatory. Charles Messier cataloged it in 1764. The Reverend William Henry Smyth gave it the name 'Wild Duck Cluster' in the 1830s, noting that the brightest stars resembled a flock of wild ducks in flight.