Strange fog or white rainbow!

[Repairman]

Across the road from me is a charming Victorian pier. Yesterday, as the fog dispersed I took some photos of a strange halo effect which I have never seen before. A perfect arc like a rainbow without the colour! Please see the pic below and let me know if you have come across this effect before.
R.

http://s691.photobucket.com/albums/vv272/Jimbophoto/

[Jerryb]

hi,
once in blue moon and depending on location i am at... i will see something similar to that ....... there called fogbows or white rainbows....

depending on the fog water droplets size you may see on the outer sides alittle color or if the fog droplets are very small in size it may appear all white...
all depends on the size of the fog waterdroplets..

[Repairman]

Thanks for identifying that as a Fogbow Jerry. I looked it up and found:-
Fog bows are caused by a diffraction of light rather than refraction and reflection. Because the fog droplets are so tiny, the wavelengths of visible light, which are obvious in the larger drops producing the rainbow, interfere with each other. The result is color bands that overlap. As the droplets get smaller, the interference is even greater, and the light that emerges is completely colorless. As with rainbows, in order to see a fog bow, you need to look in the opposite direction of the Sun.
I also caught the spectral ball effect as well which can appear at the same time. Wish I had a better camera to capture this stuff. Ho hum!
R.

[Jerryb]

hi repairman,
size of the water droplets also make a big difference...
I first saw it many years ago when i was kid out by Tulare lake , used to be a extremely large fresh water lake, but didn't think much of it at the time it was only later when one day we had unusal kind of fog around the school out teacher brought it to our attention of what it was and how it was taking place... we were studing refraction and such..smiling... I don't think see fogbow much anymore in that area... too much polution from LA and Mexico,,, and the big population increase in the area also cause increase and all of that is giving us smog instead of fog..