Sunbeams And Moonshine
Crepuscular rays are solar rays that are seen emanating from the horizon at twilight and spreading across the sky. They may be caused by clouds at or below the horizon, blocking some of the light path but allowing light to penetrate overhead in places. Similarly, a mountain range at or below the horizon may result in crepuscular rays, as the sun is blocked by the peaks and passed by the mountain passes. At other times during the day, one may see sunbeams breaking through holes in clouds or around the edges of clouds. Under these conditions, the sunlight breaking through the clouds is scattered toward the observer, and forms a contrast with those adjacent areas in which the sunlight is blocked.
Log in or Become a member to view the full text of this article.
This article may be available for purchase via the search at www.osapublishing.org.
OSA Members get the full text of Optics & Photonics News, plus a variety of other member benefits.