Thursday, December 18, 2008

A Lizard's Tale

The minor constellations are often overlooked because their stars tend to be dim and are best spotted in dark skies relatively free of light pollution. For a change of pace, it can be fun to stalk these secretive creatures when you’re away from city lights.

This is a good time of year to search the crevices of the sky for Lacerta the Lizard (luh-SIRR-tuh). Although at various times and places its unassuming star pattern was seen as a newt, a weasel, a winged serpent, and a scepter, the Lizard designation finally took hold.

The small, reptilian constellation was established in 1690 by Johannes Hevelius, a Polish astronomer and star atlas maker. It is, therefore, considered a modern constellation, rather than one of the classical constellations, which have roots in ancient cultures and are usually associated with myths and legends.

Lacerta in Bode’s 1801 star atlas
Courtesy of
Linda Hall Library of Science, Engineering and Technology

Lacerta is one of the ten smallest constellations of the Northern Hemisphere sky and fairly dim. Let’s dark adapt and see if we can tease our wriggly friend into view.

1) Face south. If you don’t know the cardinal directions at your location and you don’t have a compass, make note of where the sun sets on the horizon. That spot is approximately west. Stand with your right shoulder to the west, and you’ll be facing approximately south.

2) About an hour after sunset you should be able to spot the Great Square of Pegasus nearly overhead or, if you’re observing from a far north latitude, about a quarter of the way from the zenith (the spot directly overhead) down toward the southern horizon.

Star maps created with Your Sky

3) If you draw an imaginary line between the center of the Great Square and Deneb, the brightest star in Cygnus the Swan, you’ll cross the tip of the lizard’s tail. His body extends up towards the House of Cepheus the King.

4) Because of Lacerta’s modern origin, it has no stars with traditional names. The brightest star, which we call Alpha for its star catalog designation, is a white dwarf star.

How many of the lizard’s six zigzagging segments can you spot?