Misc - Atmospheric Optics

Light playing on water drops, dust or ice crystals in the atmosphere produces a host of visual spectacles - rainbows, halos, glories, coronas and many more.
Some can be seen almost every day or so, some are once in a lifetime sights.
Find out where to see them and how they form.
http://www.sundog.clara.co.uk/atoptics/phenom.htm