• Sun halo, a rare celestial event was seen around the Sun in the skies in Northern part of India.

About Sun Halo

• It is an optical phenomenon, which happens when sunlight passes through unique hexagonal ice crystals in the atmosphere.
• This is also called Kaleidoscopic Effect.
• Hexagonal ice crystals are found in cirrus clouds.
  • These are thin and wispy clouds and are formed very high up in the atmosphere, at a height of over 20,000 feet.
• It results in a bright ring or halo encircling the sun, which has a radius of around 22 degrees.
• It is multi-coloured and looked like a rainbow enveloping the sun.
• The halo is the brightest at the inner edge of the circular disk, with no light inside the disk as no light is refracted at smaller angles.
• Red light is refracted less than other colours of light, so the halo’s inner edge is reddish.
  • Other shades typically tend to overlap and wash out.