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Anti-crepuscular rays are beams of sunlight that appear to converge on a point opposite the sun. They are similar to crepuscular rays, but are seen opposite the sun in the sky. Anti-crepuscular rays are most frequently visible near sunrise or sunset. This photo of anti-crepuscular rays was taken at sunset in Boulder, Colorado. Crepuscular rays are usually much brighter than anti-crepuscular rays.
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Image Courtesy of Carlye Calvin

Atmospheric Optics

Have you ever seen clouds in the sky that looked different than "normal" clouds? Or have you wondered why rainbows form? Sometimes the things we see in the sky look very colorful or unique. Atmospheric optics shows us how light behaves as it passes through the atmosphere.

There are many beautiful examples like these of light and color at work in the atmosphere, including the northern lights, rainbows, sunsets, and halos. Visit the Photo Album of Atmospheric Optics and the Atmospheric Optics Image Gallery to see images of many types of these phenomena, as well as information on how they form.

Last modified February 10, 2009 by Becca Hatheway.

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF