Eighty-eight constellations blanket the sky, but they vary quite a bit in size and brightness. Some constellations are big and bright; others are small and faint. The smallest constellation is also one of the brightest: Crux, the Southern Cross, which contains four brilliant stars arranged in the pattern of a cross or a kite. Unfortunately, it's so far south that it's not visible from most of the United States.
The second-smallest constellation is visible on summer nights from nearly all latitudes. It's Equuleus, the colt. But unlike the Southern Cross, Equuleus is hardly a spectacle. In fact, its brightest star is so faint that you have to be in the suburbs or the country to see it. And the constellation covers just 72 square degrees of sky -- smaller than your hand held out at arm's length.
Still, Equuleus has a long history. It may have been invented by Ptolemy, nearly 2,000 years ago. Its brightest star is Alpha Equulei. It's a yellow star, like the Sun, but it emits much more light into space. The star looks faint because it's almost 200 light-years away.
Look for Equuleus in the east this evening. It rises around sunset, then climbs high overhead after midnight.
Equuleus isn't the only horse in the sky. Just east of the constellation is giant Pegasus, the flying horse. While Equuleus is one of the tiniest constellations, Pegasus is one of the largest -- a magnificent horse soaring across the night sky.
Script by Ken Croswell, Copyright 2009
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