Photo by Betsy Mayernick.
This week the winner is Betsy Mayernick. Her photo is not of an up-side down rainbow. Indeed it is not raining at all! This is an atmospheric gem generated by sunlight passing through ice crystals. Called a circumzenithal arc, its formation requires plate-like ice crystals falling parallel to the ground. The light enters the top of the crystal and exits one of the sides. The colors result from the dispersion of the light as it enters and exists the crystal. Because of the geometry required between you, the sun and the ice crystals, you can only see it when the sun is lower than 32 degrees above the horizon. This combination of events makes it a rare phenomenon to observe. Sundogs are also formed by dispersion of light, but sundogs are observed at the same altitude as the sun. The circumzenithal arc is observed almost directly overhead.
Photo by Betsy Mayernick.
You can send me comments.