Sun Dog

The combination of a sky full of cirrus clouds and a low sun angle made for a vivid display this late afternoon across Maryland. A second sun, and in some cases a third sun (both sides) was seen. Some think it is a sliver of a rainbow but there is no rain involved. It is just ice crystals in the cirrus clouds acting as a prism and can make for a wide array of great photos.


As I was driving home from work around 5:00 PM, from east to west on Route 32, I kept seeing great examples of sun dogs and solar halos. All I could do was wait until I got home, and then I grabbed my camera to get these two photos over the course of a five-minute time span, but with the best of the possible solar halos lost on the drive home. So what is a sun dog?


Sun Dog – Also referred to as a phantom sun or mock sun, parhelia is the formal name for a sun dog. An apparent imitation of the sun in the sky making for a bright spot to the left or right. This can sometimes display the colors of the rainbow, but yellow and orange are the most common colors. Why is it called a “sun dog,” it was thought to follow the sun, just like a loyal dog.


Solar Halo – A sun dog is actually part of a 22-degree halo or ring around the sun. This is the refraction of sunlight through ice crystals high in the atmosphere that are what make up cirrus clouds. This ring can also be seen around the moon, known as a lunar halo. When seen, it is often a signal that there is a change in weather within 24-48 hours.

Circumzenithal Arc – On rare occasions, the solar halo will have an apparent reflection with only a partial arc at the top or zenith of the view of the sun in the sky. This seems to touch the solar halo, and by itself can show up to a quarter of the circle. Some call this a smile in the sky. It is rare, but can be captured as it does get more common when the sun is lower in the sky . . . thus late in the day or fall and winter months.

Like Rainbows all sun dogs behave in the same way and in the same order. ROY-G-BIV = Red, Orange, Yellow, Green, Blue, Indigo, and Violet. The refraction of light, or break up of white light spreads out all of the colors of the visible spectrum.


I took these last two sunrise pictures through the glass of my truck, while driving in to work, back on October 22, 2007, which I had on file.


It’s always cool to see optical/meteorological phenomenon!