Earth & Sky

Moon spotlights the Great Square of Pegasus

Tonight is Sunday, Oct 12 2008

A fixture of the autumn night sky, the Great Square of Pegasus appears to the upper left of the moon at early evening. Although the almost-full waxing gibbous moon will be plenty bright, the four stars of the Great Square of Pegasus should be able to withstand the moonlight glare. By the way, if you’re a baseball fan, you might imagine these four stars as a celestial baseball diamond. Every year, the Square of Pegasus lights up the eastern sky on October evenings.

For some idea of the Great Square’s size, extend your hand an arm length from your eye. These stars are far enough apart so that the width of hand should slip in between any two Great Square stars.

Learn the Great Square of Pegasus now, and you can use these stars later to star-hop to many a celestial treasure. But you’ll have to wait until the moon drops out of the evening sky. A favorite object to find on a dark, moonless night is the Andromeda galaxy, the closest spiral galaxy to our Milky Way.

The moon and the Great Square will drift into your southern sky by late evening, and will set in the west before dawn.

Written by Bruce McClure , 12 October 08