Circles 'round the sun




Finally I have an explanation as to that strange circle around the sun I spied in Sicily. (standby for nerdy content...)

Turns out its not an omen signalling Etna's eruption (although it could have been) but is instead a 22° Halo...

"A 22° halo is a rather frequently appearing halo, an optical phenomenon forming a circle 22° around the sun, or occasionally the Moon. It forms as sunlight is refracted in hexagonal ice crystals suspended in the atmosphere. As the light beam passes through two sides of the prism forming a 60° angle, the angle of minimum deviation is almost 22° (e.g. 21,84° in average; 21,54° for red and 22.37 for blue.) This wavelength-dependent variation in refraction causes the inner edge of the circle to be reddish while the outer edge is bluish. " Wikipedia

So there you have it!

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