Sun Dog Variations
This photograph taken today by Larry Carlson shows the typical sun dogs but with a twist. There is another bright light at the top of the arc, forming what appears to be a big, bright smile. This optical illusion is called a circumzenithal arc. It is rarer that the standard wintertime sun dogs, but the cause is more or less the same. The sun dogs, the circumzenithal arc, and the halo are all caused by suspended ice crystals in the air which is a result of today's wind and blowing snow. The source of all the bright light in the photo is the sun. But ice crystals in the locations of the dogs, the arc, and the halo, are in just the right position to deflect some of the rays headed in their direction into your eyes. So technically, this is all an optical illusion. You would not be able to see any of this from an airplane overhead because the lights are not really there.
Attached to this page is another somewhat rare variation of a sun dog; the double sun dog. This picture was taken Saturday morning by Kathy Reynolds. a double sun dog is similar to a double rainbow. If she had used a camera lens wide enough, you would be able to see the sun in the middle and two complete sets of sun dogs on either side for a total of four sun dogs.
Meteorologist John Wheeler