Anticrepuscular rays

Anticrepuscular rays converging to the antisolar point, viewed from above
Anticrepuscular rays opposite the setting sun off the Florida Gulf Coast of the United States
Anticrepuscular rays and double rainbow opposite the setting sun on the northern shore of Lake Ontario

Anticrepuscular rays or antisolar rays[1] are similar to crepuscular rays, but seen opposite the sun in the sky. Anticrepuscular rays are near-parallel, but appear to converge at the antisolar point because of linear perspective.[2] Anticrepuscular rays are most frequently visible near sunrise or sunset. Crepuscular rays are usually much brighter than anticrepuscular rays. This is because for crepuscular rays, seen on the same side of the sky as the sun, the atmospheric light scattering and making them visible is taking place at small angles (see Mie theory).

Although anticrepuscular rays appear to converge onto a point opposite the sun, the convergence is actually an illusion. The rays are in fact (almost) parallel, and their apparent convergence is to the vanishing point at infinity.[3]

References

  1. ↑ Cowley, Les, "Anti-solar (anti-crepuscular) rays", Atmospheric Optics, retrieved March 19, 2015
  2. ↑ John A. Day (2005), The Book of Clouds, Sterling Publishing Company, Inc., pp. 124–127, ISBN 978-1-4027-2813-6, retrieved 2010-10-09
  3. ↑ Cowley, Les, "Antisolar rays", Atmospheric Optics, retrieved March 19, 2015

External links

Anticrepuscular rays are visible in the right of this panoramic photo of Chandler, Arizona
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