Karl Diefenderfer captured this sundog on March 6, 2017, in the skies over Philadelphia, Pennsylvania. It’s what’s called a sundog, really a piece of a larger halo, called a 22-degree halo, although the entire halo might not have been visible to Karl. Sometimes only the sundogs are visible. If you do see the entire halo, notice that the sundog is red-colored towards the sun, sometimes with greens and blues beyond, as in Karl’s photo.
Les Cowley, who lives in the UK and creates the great website Atmospheric Optics, publishes many photos of halos created by the sun and moon. He has this to say about them on his page about Frequent Halos:
Halos appear in our skies far more often than do rainbows. They can be seen on average twice a week in Europe and parts of the United States. The 22-degree radius circular halo and sundogs (parhelia) are the most frequent.
By the way, after we first published Karl’s photo (top of this post), we received a second, very beautiful sundog photo from Eliot Herman in Tucson. It’s below. Enjoy!
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Prior to that, she had worked for the University of Texas McDonald Observatory since 1976, and created and produced their Star Date radio series. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. In 2020, she won the Education Prize from the American Astronomical Society, the largest organization of professional astronomers in North America. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.
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