Hyderabad witnesses rare '22 degree Sun's halo’ phenomenon, here's what it means

(Image courtesy: Twitter/@deepthiis)

New Delhi: Telangana on Wednesday witnessed a rare phenomenon of a rainbow-coloured ring around the sun. People took to social media to report the marvellous event as the ‘halo’ appeared around the sun, just last week this was seen in Bengaluru as well. 

The rare optical and atmospheric phenomenon takes place due to the dispersion of light is called ‘22 degree circular halo' as a ring with an apparent radius of approximately 22° around the Sun or Moon. When visible around the Moon, it is called a moon ring or winter halo.

What is Sun's Halo?

The Sun's halo that was seen around parts of Telangana is a 22-degree ring that appears due to the dispersion of light as white light passes through ice crystals found in upper-level cirrus clouds, causing the halo to have colours. 

The EarthSky.org explained the event caused by both refraction, or splitting of light, and also by reflection, or glints of light from these ice crystals.

"The crystals have to be oriented and positioned just so with respect to your eye, in order for the halo to appear. That’s why, like rainbows, halos around the sun – or moon – are personal. Everyone sees their own particular halo, made by their own particular ice crystals, which are different from the ice crystals making the halo of the person standing next to you," it said in an article. 

During the process, light undergoes two different refractions once when it passes through ice crystals and the second when it exists. During the two phases, it bends depending on the diameter of the ice crystal and the two refractions bend it by 22 degrees from its original point giving it the name of a 22-degree ring.

This phenomenon was spotted in Tamil Nadu's Rameswaram in 2020 as well.