Moon Dogs

By Bob Berman
January 21, 2009
Moon Dogs
Matin Turner

Ever seen a Moon dog?

When the Moon is low in the sky, a bright “false Moon” (a well-defined saucer of brilliant moonlight) may hover off to its side.

Sometimes, these “saucers” are distinct bright spots attached to a halo around the Moon at a point 22° to its right or left—or both sides at once. Often, however, they may seem to appear without the halo.

By day, with the Sun, one of these phenomena is called a parhelion, or sun dog. By night, it is called a paraselene, or Moon dog.

Look for a Moon dog when you see high, thin, cirrus clouds near the Moon.

Photo of Moon Dog

Photo of Sun Dog by Donna Winsted


The 2005 Old Farmer's Almanac


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Altho I am old and I have

Altho I am old and I have lived in northern Illinois most of my life, I have only heard of SUN dogs. Also, I was told as a youngster that there is weather folklore around sun dogs, i.e., a change in the weather. Do YOU have a comment? Thank you... Dean

Hi, Dean, Yes...Sun dogs,

The Editors's picture

Hi, Dean, Yes...Sun dogs, also called mock Suns or parhelia, look like second Suns in the sky, appearing at the same height of the Sun and to its right and/or left by 22 degrees or more. They are caused by light that is refracted through ice crystals in the atmosphere (as through a prism) and exhibit the colors of the rainbow.