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Moon and Stars

June 4, 2011

A star that's known as a leader is following the star it normally leads into a sort of celestial limbo right now. But it'll once again lead the way come the dog days of summer.

The star is Procyon -- a Greek name that means "before the dog." The name indicates that, from most northern latitudes, it rises a little bit before Sirius, the Dog Star -- the brightest star in the night sky.

Right now, though, you can't see either one of them rise because they do so during the daylight. But you can see Procyon as it sets. Tonight, in fact, it's to the lower left of the Moon as darkness falls. Pollux and Castor, the "twins" of Gemini, are about the same distance to the upper right of the Moon.

By the time the sky darkens enough to see Procyon, Sirius has already dropped below the horizon -- so the "follower" is actually leading the leader as they set.

In ancient times, Procyon's role as a herald of Sirius was more than just a curiosity. Sirius was one of the most important stars in the sky. In Egypt, for example, the year began when Sirius was first sighted in the dawn sky. So the first appearance of Procyon alerted the Egyptians that the time for new year's festivals and ceremonies was almost at hand.

In a few days, Procyon will disappear in the evening twilight, just as Sirius has. They'll stay hidden in the sunlight until around the beginning of August, when Procyon will once again lead the Dog Star into the dawn sky.


Script by Damond Benningfield, Copyright 2011


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