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June 19, 2020 at 12:52 am
#436897
Gavin Pretor-Pinney
Keymaster
Annie,
That’s an optical effect known as a 22-degree halo. It’s a ring around the Sun (or Moon) with a reddish inner edge. It is caused by the sunlight shining through hexagonal shaped ice crystals each of which acts like a tiny prism that refracts and reflects the light. It gets its name from the fact that, no matter where it appears in the sky, it always appears the same size –with the angle between the center, the Sun, and the ring of the halo being 22 degrees.
well spotted!