Star cluster takes name from Egyptian queen

Image: Coma Berenices
From midnorthern latitudes, Coma Berenices can be seen in the eastern sky after twilight has ended. Look for a scattering of stars between the tails of the Great Bear and the Lion.
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During last February's total lunar eclipse I was emceeing an eclipse party at my local town park. About 150 people gathered to watch the eclipse through a variety of different instruments. During the 50-minutes that the moon was completely immersed in the Earth's shadow, the sky had darkened considerably and allowed us to see many of the fainter stars and constellations.

It was while I was talking about our old friend, Leo the Lion, that someone in the crowd asked me to identify a "tiny cloud of light" situated between Leo and the Big Dipper. "Believe it or not," I replied, "you're looking at the celestial wig."

And with that I launched into the story of Berenice's Hair.

A queen who "wigged out!"
While virtually all of the constellations are named for mythological people, beasts and inanimate objects, Berenice's Hair (known as Coma Berenices) is actually associated with a real person. Eratosthenes in the 3rd century B.C. was among the first to make note of this faint group of stars. This pattern of stars is actually a large, loose star cluster some 250 light-years away. And indeed, to the unaided eye it appears as a faint shimmering patch of light on clear moonless nights.

As a cluster, Coma Berenices is by far at its best in a pair of good binoculars. If, on the other hand you attempt observation of it with a high-powered telescope the impression of a cluster will become totally lost because of the telescope's narrower field of view.

Berenice II was an Egyptian queen, the wife of Ptolemy Euergenes (also known as Ptolemy III), the king of Egypt, who reigned around 250 B.C. The story goes that Berenice sacrificed her beautiful amber tresses and placed them in the temple of Aphrodite at Zephyrium as she vowed to do if her husband returned victorious from his war against Syria. Shortly after the royal couple's happy reunion, however, the hair mysteriously vanished, apparently stolen from the temple.

As you might expect, when Berenice found out what had happened she was (to put it mildly) ticked off.

But it was Conon of Samos, a court astronomer and mathematician, who eventually convinced the disconsolate queen that the gods had taken her beautiful locks and placed them up in the sky, for all to admire. Such is the story of how the cluster probably received its moniker, though this region was not generally recognized as the separate constellation of Coma Berenices until the beginning of the 17th century. Initially, in fact, many of the star atlases of that era did not depict this star cluster as a celestial hairpiece.

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Indeed, in various star maps of the late middle ages the cluster was identified as a rose-wreath or ivy-wreath, and occasionally as a sheaf of wheat held in the hands of the nearby constellation Virgo. Others saw it as the hair of Sampson, not Berenice, while still others regarded it as a tuft at the end of the tail of Leo, the Lion. Credit is usually given to the astronomer Tycho Brahe for first cataloguing it officially as Coma Berenices in the year 1602.

No milk for you tonight!
The sight of Coma Berenices high in the sky is bad news, if you are a fan of the Milky Way.

Just to the east of this cluster is the north galactic pole, one of two points in the sky lying farthest from the ghostly circle of light that composes the Milky Way. As darkness falls this week, the cluster is about halfway up in the eastern sky, while the wintertime branch of the Milky Way appears about halfway down in the west. As the night progresses, and as the cluster rises higher, the Milky Way is dropping lower. When the cluster passes almost directly overhead around 1 a.m. local daylight time, there is little to be seen of the Milky Way itself; for it then runs completely around the horizon and is most always obliterated by the thicker layer of haze that perpetually rims the horizon.

Conversely, when the cluster is rising or setting, the Milky Way appears to arch high across the sky. Nowadays, you'll have to get up just before dawn breaks to get such a view.

Or as Hans A. Rey (1898-1977) noted in his now classic book, The Stars, A New Way to See Them: "Thus, no hair can ever get into the milk, celestially speaking."