|Subhorizon Red Rainbow A capture by Franck Grondin (Frog 974 Photographies) as light rain fell close to sunset. Réunion Island, "Cap Noir" viewpoint.
All images ©Franck Grondin, all rights reserved. Shown with permission
|Sub Horizon Bows
All rainbows are circular (or nearly so). They will form a full circle if allowed by plentiful raindrops in the right directions.
On level ground the path length from the eye to ground is not long enough to include enough rainbow forming raindrops. At most a faint bow is seen.
Climb a hill or mountain or stand on the Grand Canyon rim and there is a plentiful supply of rain along the rainbow cone.
|The primary rainbow has its centre directly opposite the sun. At sunset or sunrise the bow is at its greatest possible height.
At sun heights above 42° the entire bow is beneath the horizon