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Arc and 2 sundogs over Illinois

Halos like this one around the sun or moon are caused by ice crystal high in Earth’s sky. Notice the upside-down rainbow-like arc above. It’s called a circumzenithal arc.

Photo by Russ Adams.

Russ Adams in Pike County, Illinois caught this beautiful scene on December 22, 2016. The upside-down rainbow-like arc above is called a circumzenithal arc. The circle around the setting sun is called a 22-degree halo, and this halo has two sun dogs, or bright spots, visible on it.

Amazing and beautiful catch, Russ! Thank you.

Click here to learn the names of the parts of ice halos.

Deborah Byrd


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