What's New
  Rays & Shadows
    Crepuscular rays
       More images
    Cloud shadows
    Mountain Shadow
    Earth's Shadow     Blue Sky 
    Sunset Mirages
    Green Flash
    Opposition effect
  Water Droplets
  Ice Halos
  High Atmosphere
  Links & Resources
  Search - Index


   Anti-solar (Anti-crepuscular) rays  

  Rays in the east opposite the setting sun the foreground and clouds are still sunlit. Leigh Hilbert (site) caught these anti-crepuscular rays on 3rd March 2004 in Washington State. ©2004 Leigh R. Hilbert shown with permission.
Crepuscular rays appear to converge on the sun, anticrepuscular or antisolar rays converge in the opposite direction and you must have your back to the sun or sunset point to see them. They appear to converge towards the antisolar point, the point on the sky sphere directly opposite the sun. Like crepuscular rays they are parallel shafts of sunlight from holes in the clouds and their apparently odd directions are a perspective effect. Think of a long straight road, it converges towards the horizon but turn around and it also converges to the opposite horizon.   Crepuscular and anticrepuscular rays behave in the same way. 

Anticrepuscular rays are not rare but they must be sought carefully. When ordinary crepuscular rays are visible, turn around and search for their opposite numbers.   More rarely, sunrays pass right across the sky.