Fogbow: a White Rainbow over Big Red

White Rainbow, photo by stevedontsurf.

Today’s photo shows a fogbow. According to the Fogbow entry from Atmospheric Optics:

Fogbows form in the same way as rainbows. A small fraction of the light entering droplets is internally reflected once and emerges to form a large circle opposite the sun.

But… …beyond that there are major differences. Rainbows are formed by raindrops which are so large that rays passing through them follow well defined ‘geometrical optics’ paths. Fogbows are formed by much smaller cloud and fog droplets which diffract light extensively.

…Fogbows are almost white with faint reds on the outside and blues inside. The colours are so washed out because the bow in each colour is very broad and the colours overlap.

Read on for more, including some photos and get a little more at Wikipedia’s page on fog bows.

Steven shot this at the Holland Harbor Lighthouse aka Big Red and writes that he’s still amazed he was able to stumble upon one of these. Check his photo out big as the sky and in his Holland slideshow.