When the sun was an enchanting sight

The halo effect around the sun on Tuesday. — Photo: T.L.Prabhakar

The halo effect around the sun on Tuesday. — Photo: T.L.Prabhakar  

IF YOU thought you achieved something by that zigzag-zoom ride on your motorcycle to reach home or office on Tuesday morning, you missed something spectacular — solar halo.

A solar halo is rarely seen though it is as frequent as the halo around the moon. On Tuesday, inquisitive sky-gazers called the Nehru Planetarium to find out what was happening in the sky. H.R.Madhusudan, Science Educator at the Planetarium, said ice crystals in the earth's atmosphere caused the solar halo. Tuesday's halo was caused by the hexagonal ice crystals, which in their micro-size could resemble "HB pencils". When the sunlight passes through these crystals, it is refracted into its constituent colours. And you have the colourful halo.Although it is a regular phenomenon, very few spot it. For the record, Tuesday's halo was 22 degrees in size. According to Mr. Madhusudan, the size of the moon is half a degree in the jargon of astronomy. In other words, Tuesday's solar halo was 44 times the size of the moon. Of course some times a solar halo is as large as 44 degrees.

November, December, and January are the best months to see solar halos.

By Govind D Belgaumkar

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