January 27, 2007
The photo above showing brilliant iridescence at sunset was captured from southern Switzerland (Caslano) on October 30, 2006. Irisation or iridescence usually occurs relatively close to the Sun, but in this case, the metalic colors were distributed over the western sky. Diffraction of sunlight by water droplets having a uniform size interferes with the Sun's rays in such a way to produce the opalescent hues. The photographer is looking toward Ponte Tresa, in northern Italy.