Anticrepuscular Rays Over Horseshoe Canyon

Astronomy Picture of the Day · 2003-02-26 · NASA (public domain)

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Anticrepuscular Rays Over Horseshoe Canyon — APOD for 2003-02-26

What's happening over the horizon? Although the scene may appear somehow supernatural , nothing more unusual is occurring than a setting Sun and some well placed clouds. Pictured above are anticrepuscular rays . To understand them, start by picturing common crepuscular rays that are seen any time that sunlight pours though scattered clouds. Now although sunlight indeed travels along straight lines , the projections of these lines onto the spherical sky are great circles . Therefore, the crepuscular rays from a setting (or rising) sun will appear to re-converge on the other side of the sky. At the anti-solar point 180 degrees around from the Sun , they are referred to as anticrepuscular rays . While enjoying the sunset after dinner near Horseshoe Canyon in Utah , the photographer chanced to find that an even more spectacular sight was occurring in the other direction just over the canyon -- a particularly vivid set of anticrepuscular rays .

Astronomy Picture of the Day for 2003-02-26 — image & explanation courtesy of NASA (public domain), mirrored at Tukuk-OS for reading and search convenience.

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