Mars and a Colorful Lunar Fog Bow
As seen on Astronomy Picture of the Day even from the top of a volcanic crater, this vista was unusual. Mars was bright when this picture was taken in January 2010, as it was nearing its opposition and the brightest time in every two years (note the beautiful Beehive star cluster above Mars in this view). Arching across the lower part of the image is a rare lunar fog bow. Unlike a more commonly seen rainbow, which is created by sunlight reflected prismatically by falling rain, this fog bow was created by moonlight reflected by the small water drops that compose fog. Although most fog bows appear white, all of the colors of the rainbow were somehow visible here. The above image was taken from high atop Haleakala, a huge volcano in Hawaii, USA.