Atmospheric
Optics
Low Rainbow
~ Magnus Hoog
imaged this bow in northern Sweden from a hillside. The colourful bow nestles in the land below the horizon.
Image ©Magnus Hoog.
Sun 42° high
The rainbow's centre is 42° below the horizon and its tip grazes the horizon.
The familiar primary and secondary rainbows (there are others) have their centres directly opposite the sun. As the sun climbs the rainbow sink. On level ground we can only see a primary rainbow in the sky when the sun is less than 42° high - the radius of the bow.
Sunrise
The centre of the rainbow is also on the horizon and its tip is 42° high
