Jimmy Westlake: The Scutum Star Cloud
August 24, 2010
Steamboat Springs — Most of the 88 official constellations in the sky represent mythological characters passed down to us from the Babylonian, Greek and Roman civilizations thousands of years ago. This includes many of our familiar constellations such as Orion the Hunter and Ursa Major, the Great Bear. Others are more recent additions to the sky, only a few centuries old, such as Antlia the Air Pump and Horologium the Pendulum Clock.
There are only two constellations, however, that can be traced back to actual historical figures. One is Coma Berenices, a spring constellation representing the hair of Queen Berenices of Egypt. The other is the summer constellation Scutum Sobiescianum, or just Scutum for short. It represents the shield of John Sobieski, the Polish king who defeated the Turks in the 1683 Battle of Vienna.
By chance, King Sobieski was a friend of famed Polish astronomer Johannes Hevelius, and seven years after the Turks were defeated, Hevelius invented the constellation of Scutum Sobiescianum, Sobieski's Shield, to honor his king. Hevelius is credited with inventing seven of our 88 constellations. In addition to Scutum, he invented Canes Venatici (the Hunting Dogs), Lacerta (the Lizard), Leo Minor (the Little Lion), Lynx, Sextans (the Sextant) and Vulpecula (the Fox).
Scutum is an obscure little constellation, to be sure, with no star brighter than fourth magnitude and ranking only fourth in size among all the constellations. Even so, it is an easy constellation to find in the summer sky and well worth the effort to locate because it includes one of the brightest patches of the summer Milky Way within its borders, the so-called Scutum Star Cloud. Only the Sagittarius Star Cloud, located farther to the south, outshines the Scutum Star Cloud. On any dark, moonless summer night, the Scutum Star Cloud stands out prominently against the black sky. Look for it this month in the early evening, high in the southern sky on a line about midway between the two bright summer stars Altair and Antares.
An ordinary pair of binoculars will magically transform the Scutum Star Cloud into thousands of glittering stars, and you should be able to spot the famous Wild Duck star cluster. Discovered by Gottfried Kirch in 1681, the Wild Duck cluster became the 11th object in Charles Messier's famous catalogue of star clusters, galaxies and nebulae in 1764 and often is referred to by its Messier number, M11. The brightest of M11's 3000 stars form a distinctive "V" shape, resembling a wedge of flying ducks. These twinkling ducks and the rest of the Wild Duck cluster stars are winging their way through the Milky Way at a distance of 6,000 light years from Earth.
Jimmy Westlake teaches astronomy and physics at Colorado Mountain College's Alpine Campus. He is an avid astronomer whose photographs and articles have been published all across the world. His "Celestial News" column appears weekly in the Steamboat Today newspaper and his "Cosmic Moment" radio spots can be heard on local radio station KFMU. Check out Jimmy's astrophotography website at http://www.jwestlake.com.