Kolkata: India missed the spectacular Great American Eclipse that was viewed across North America on Monday with the ring of fire and the twin diamond rings, once just before the total eclipse and the other just after it. Kolkata, however, witnessed another phenomenon on Tuesday morning when a halo formed around the sun.
However, unlike the total solar eclipse that is a celestial phenomenon, the halo was formed due to meteorological conditions.Known as the 22° halo, it is an atmospheric optical phenomenon that consists of a halo with an apparent radius of approximately 22° around the sun. The 22° halo also appears around the moon, which is known as the moon ring.
“The 22° halo is typically formed when cirrus clouds are formed around 5-15km up in the sky. These clouds contain millions of tiny hexagonal ice crystals. The halos are caused by both refraction, or splitting of light, by reflection or by glints of light from these ice crystals,” explained Debiprasad Duari, former director of M P Birla Planetarium.
The inner part of the ring is typically reddish in hue while the outer boundary is bluish — giving us a near perfect circular rainbow effect.
The total solar eclipse that was viewed in North America began at 9.13pm on Monday in India and concluded at 2.22am on Tuesday. At IISER-Kolkata, scientists saw the solar eclipse on a livestream feed from NASA. The solar activity this time was near the peak. The solar eclipse was visible over a large stretch from the south-west to north-east of the US.
“An Indian team has gone to Texas to watch the event. We prepare models of the eclipse based on the observation,” said Dibyendu Nandi, head of the Center of Excellence in Space Sciences at IISER, Kolkata.