DENVER — So many sent in photos Friday afternoon showing what looks like rainbows. The clouds aren’t made of raindrops and the sun is in front of us, not behind us as it would be for a rainbow.
So, what are these things? Well, a couple possibilities out there Friday.
Sundogs are the first option. A sundog is a brightly refracted area of sunlight to the right or left of the sun. Here is an example:
That bright spot with “rainbow colors” to the right is the sundog. The clouds producing that feature are made of ice.
Icy high clouds can refract sunlight at a specific angle. If you happen to be in that perfect ‘line of sight’ you can see the spectrum of colors, as in that photo.
The second option of what you saw today is a halo.
If there are a lot of high clouds, like there were Friday afternoon, you’ll actually be able to see a nearly full, or full, halo around the sun. (Sundogs will appear along that ring directly left and/or right of the sun.)
Any section of that halo may show you the spectrum of colors if you are in that exact line of sight needed between you, the clouds, and the sun.
Here’s an example of the halo showing us the color spectrum, again these clouds are made of ice and not rain producers:
Of the two features in our sky Friday, sundogs are the brightest ones as they are sending an intense beam of sunlight toward your eye. In either case, you have to be in the right spot and the right time or your angle to the clouds and sun just isn’t going to give you the beautiful ‘rainbow colors’.
Rainbows, in the traditional sense, are made differently. They form when sunlight comes from behind you toward rain that is in front of you. Technically speaking, the angle of refraction is 40 to 42 degrees whereas a sundog and halo will be either 22 or 46 degrees.