It has been known to stargazers since the time of the Greek writer Aratos in 260 B.C. In 130 B.C., Hipparchus included it in his star catalog and called it “Little Cloud.” And second-century astronomer Claudius Ptolemy described it as “The Nebulous Mass in the Breast (of Cancer).”
Today it's known to astronomers as M44 – the Praesepe (pruh-SEHP-ee) or Beehive star cluster. It's some 577 light-years (3.5 quadrillion miles) away in the faint zodiacal constellation of Cancer, the Crab.
To see this cluster, you need a clear, dark sky, so this week isn't an ideal time to look for it. But once the moon leaves the early evening sky late next week, you can spot it low in the western sky after dark. During mid-May the Beehive can be found to the left of the “twin” stars Castor and Pollux, and above the bright star Procyon.
The cluster is quite faint. But between May 20 and 24, Mars passes right in front of the Beehive and acts as a beacon to draw you in. Even with binoculars, Mars' tiny orange disk will produce a lovely sight against the dozens of shimmering stars of the Beehive.
Ancient sky watchers used this star cluster to forecast the weather. The philosophers Aratos and Pliny wrote that when they could see the cluster, the skies would be fair, but when they couldn't, a storm must be on its way. Today we know their technique works fairly well because the high cirrus clouds that often precede a storm can blot this cluster from view while leaving the rest of the sky unaffected.
The ancient sky watchers had no idea what the cluster's true nature was. That discovery came in the early 17th century, when astronomers aimed the newly invented telescope in its direction. Today, even inexpensive binoculars show the Praesepe as a beautiful cluster of many dozens of faint stars.
© Copley News Service
