14 July 2010

A Sun Halo Over Bangalore

Last Sunday the 11th of July many in Bangalore witnessed a big halo around the sun. Around noon when the Sun was almost at the zenith, there was a rainbow like ring around the sun.



This fairly common sight occurs when high thin Cirrus clouds cover much of the sky. Typically found at heights greater than 20,000 feet (6,000 meters), cirrus clouds are composed of ice crystals that originate from the freezing of supercooled water droplets. Each ice crystal acts like a tiny lens.
Most of these crystals have a similar elongated hexagonal shape and light entering one crystal face and exiting through the opposing face refracts 22 degrees, which corresponds to the radius of the Sun halo.
Similar halo can be seen occasionally round the moon too...

If you saw the halo, leave a comment and tell us about your experience.

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