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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. |
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