Three "squiggly" constellations wiggle across the sky on winter evenings. Draco, the dragon, is in the north, wrapping around the North Star. Eridanus, the river, trickles across the southwest. And Hydra, the sea serpent, slithers into view in the southeast.
It's hard to "see" these constellations because they're long streamers of stars that twist and turn between more prominent star patterns. There are none of the boxes or triangles or semicircles that make some other constellations stand out. And they have few bright stars.
The most famous of the three is Draco. It's been prominent in the skylore of many cultures. But that's mainly because of its position in the sky: Several thousand years ago, one of its stars was the North Star. That's because Earth wobbles on its axis. As it wobbles, the north pole points at different stars. Today, it points at Polaris. But almost 5,000 years ago, it aimed at Thuban in Draco.
Hydra is the longest of all the constellations. It's so long that while its head rises around sunset, its tail doesn't clear the horizon until well after midnight. In mythology, it had a frightening power: When its head was cut off, two new heads grew in its place.
Eridanus is the easiest of the three constellations to find because it has a bright companion -- Orion. Eridanus begins just to the lower right corner of Orion's rectangular frame, and twists down to the west and south. More about Eridanus tomorrow.
Script by Damond Benningfield, Copyright 2008
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