The peak of this year’s Perseid meteor shower occurs on the evening/morning of Aug. 12/13. The best display will occur during the last few hours before morning twilight on Aug. 13. A 55-percent illuminated first-quarter moon will spoil the view until it sets at 11:20 p.m. on Aug. 12.
So hang in there through the relatively meteorless early evening until the rising sun spoils the view.
While you’re waiting, consider spending a few moments examining the constellation Scutum and its glowing patch of Milky Way, the Scutum Star Cloud (SSC), with a set of binoculars.
You’ll find the obscure constellation nestled among the stars of Aquila to the northeast, Ophiuchus to the west, and Sagittarius to the south.
There isn’t much to see, constellationally speaking — three faint, barely naked-eye stars arranged in a flat triangle.
Despite the Scutum Star Cloud’s beauty, the ancients never gave the area a name because of the relative faintness of its stars. The area remained undesignated until Johannes Hevelius came onto the scene.
His exquisitely drawn star atlas was published in 1690, three years after his death. In a stunningly obvious example of currying political patronage, he named the constellation Scutum Sobieski, the Shield of Sobieski, after the renowned Polish leader. Modern astronomers shorten the name to Scutum, the Shield.
In the midst of the constellation is a bright patch of Milky Way called the Scutum Star Cloud. Within the SSC is the Wild Duck Cluster, one of the sky’s most eye-pleasing telescopic showpieces. Look in binoculars for a small, bright, fuzzy patch near the center of the SSC.
Gottfried Kirch first spied it telescopically in 1681. In 1764, Charles Messier cemented its notoriety by including it as the 11th entry in his list of diffuse, comet-like objects, the renowned Messier catalog. More than two centuries later, amateur astronomers still call it M11.
In 1844, William Smyth wrote that M11 “somewhat resembles a flight of wild ducks” flying in a V-formation. Even though their larger telescopes have erased M11’s ducks-in-flight appearance, amateur and professional astronomers occasionally refer to M11 as the Wild Duck Cluster.
“Open clusters,” as such star collections are named, are born from gigantic clouds of glowing hydrogen gas called “gaseous nebulae.” A similar nebula gave birth to our own sun and, in fact, every other star you see.
The process is ongoing. New stars are condensing in faraway nebulae right now.
The clouds are exceedingly thin, so we shouldn’t be able to see them. Luckily, the young stars inside them ionize the gas and cause it to glow.
The process is similar to what happens in a fluorescent light bulb, where a spark of electricity ignites the gas and causes it to shine. In the case of gaseous nebulae, the fluorescent light bulbs are hundreds of trillions of miles wide.
Many nebulae contain enough hydrogen to produce thousands of stars. Stars are thus born in litters, like puppies. Early in their lives, they huddle close to their cosmic mother.
Star birth consumes much of a nebula’s available hydrogen gas. The powerful explosions of the young stars often blow the remaining gas outward into space.
The result is an object like M11, a dense congregation of young stars without a visible trace of surrounding hydrogen gas.
The Wild Duck is among the most massive open clusters known — 11,000 solar masses packed into 1,000 stars.
At a distance of 6,000 or so light-years, one might expect it to look small in a telescope. (One light-year is equivalent to 5.9 trillion of your Earthling miles.)
However, M11 is also one of the most voluminous open clusters known. At 190 light-years wide, it nicely fills a medium-power telescope field.
As in most open clusters, the stars of M11 are youngsters at only 300 million years old.
M11’s stars are only weakly held together by gravity. They may be close together by galactic standards, but they aren’t close enough to maintain their distance from each other for long.
As the cluster’s stars grow older, passing Milky Way stars will drag M11’s stars away from their birthplace, and the Wild Duck cluster will be no more.
Enjoy it while you can. In a few hundred million years, it will be too late.
Tom Burns is the former director of the Perkins Observatory in Delaware.
