Regenboog, driekwart cirkel gefotografeerd bij de Grand Canyon
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Regenboog, driekwart cirkel gefotografeerd bij de Grand Canyon
Regenboog, driekwart cirkel gefotografeerd bij de Grand Canyon
To see a rainbow, all you need are sunlight and falling rain. Correction: that's all you need to see half a rainbow. Typical rainbows are at least 50% hidden below the horizon. To boost the fraction, add a canyon. David Blanchard saw almost 75% on July 1st:
"Late afternoon thunderstorms gave way to sunlight just moments before sunset, resulting in this three-quarter circle rainbow," says Blanchard, who was standing on the south rim of the Grand Canyon when he took the picture.
His photo shows that rainbows are not just arcs, but actually circles. Moreover, they are double circles. The interior or "primary rainbow" is caused by one reflectioninside raindrops. The exterior or "secondary rainbow" is caused by two reflections. Turns out, you can learn a lot about rainbows by standing on a precipice.
Bron: http://www.spaceweather.com/
