How to find it
The Wild Duck Cluster (Messier 11) is found in the constellation Scutum the Shield, just south (or below) the Eagle’s Tail in the constellation Aquila the Eagle. Unless you have eagle eyes, don’t expect to see this distant star cluster with the eye alone. It’s much easier to spot this deep-sky gem with binoculars.
To star-hop to the M11 Wild Duck Cluster, first of all find Altair, the brightest star in Aquila the Eagle, and the second brightest star in the Summer Triangle. Altair is rather easy to identify, because it’s flanked on each side by the two moderately bright stars, Tarazed and Alshain.As displayed on the sky chart, jump to the southwest (lower right) of Altair to locate Delta Aquilae, this landmark star residing about 8 degrees from Altair. For reference, the width of four fingers held at an arm length approximates 8 degrees of sky. Once you find Delta Aquilae, keep descending downward, going a bit more than twice the Altair/Delta Aquilae distance. In your binoculars, you’ll see a semi-circle of stars that pretty much fills your binocular field. The Wild Duck Cluster pops out as a hazy star-like object just beneath this semi-circle pattern of stars.
The Wild Duck Cluster is best viewed with a telescope and when it’s relatively high in the southern sky. That’s in the wee hours before sunrise in spring, late night in early summer, and mid-evening in late summer and early fall.
Science and History
The M 11 Wild Duck cluster is an open star cluster like the Pleiades and the Hyades, except that it’s much farther away. The Pleiades and Hyades cluster lie about 430 light-years and 150 light-years away, respectively, whereas the Wild Duck Cluster resides some 5,500 light-years distant. It was discovered in 1681 by Gottfried Kirch, and was probably first resoved into stars by William Durheim around 1733.
At first glance, the Wild Duck Cluster looks like a globular cluster, like M13 and M5. M11 is one of the richest and most compact of open star clusters, composed of a few thousand hot, young stars that are only a few million years old. Globular clusters, on the other hand, contain tens to hundreds of thousands of stars that are billions of years old.
The 19th century observer Admiral Smyth thought the distinctive wedge-shape group of stars in M11 resembled a flock of wild ducks flying by, hence the nickname Wild Duck Cluster. The luminosity of many of M11′s stars exceeds that of the sun by a hundredfold. If we lived on a planet within this star cluster, we’d see hundreds of first-magnitude stars filling the nighttime, with many of these stars outshining Sirius, the brightest star to shine in Earth’s night sky.
The M11 Wild Duck Cluster is positioned at RA: 18h 51m 6s; Dec: 6 degrees 16′ south