Art in the sky
HYDERABAD : It was not just another Wednesday morning in Hyderabad. The residents of the City of Pearls were in for a visual treat -- a breathtaking view of the sky when a rainbow-like ring hugged the Sun. In a couple of hours, pictures and queries about this optical phenomenon, known as a ‘sun halo’, flooded social media platforms.
A sun halo is formed when light reflects from ice crystals high up in the atmosphere. According to the India Meteorological Department (IMD), this is not a celestial phenomenon but a meteorological one, just like rainbows. Halos require ice crystals to form — either from high cirrus cloud or free-falling crystals. The halo first appeared at 11 am and was visible for about an hour and a half. Unlike celestial phenomena, the halo cannot be predicted. So, it is always better to ‘keep a patch of sky bove your head’.
“Typically, sunlight is reflected by the ice crystals from the cirrus clouds which lie very high in the atmosphere. This emanates a white halo and sometimes, even gives out rainbow-like colours. If the light rays strike the light at a particular angle, in this case 22 degrees, some light may be refracted, forming a halo. The same is the case with the Moon sometimes,” says BG Siddharth, director of the BM Birla Science Centre.
Unlike celestial phenomena, the sun halo is common and very often goes unnoticed. “It is observed during the monsoon when the sky is filled with cirrus clouds. Many fail to observe the phenomenon and it was mostly hidden in plain sight, just like the Moon is sometimes during the day,” Siddharth says.
According to Siddharth, people are more observant these days as they have time to spend with themselves, their family and nature. “The halo was observed around the Sun and even the Moon during the same time last year and the year before that,” says Raghunandan Rao, founder of The Indian Planetary Society.
The frequency of it being observed usually depends on the intensity of the ring. “Sometimes, like today, it was bright. Most often, it is visible only through neutral filters,” he adds.
Moon halos are usually bright without any colours. It is very rare for it to take the form of a faint rainbow. On May 24, Bengaluru witnessed a similar spectacle in the sky. Last week, Hyderabad saw a supermoon partially covered by fast-moving clouds. There are more such phenomenons likely to occur in the city in the near future. Keep your eyes open and don’t miss them.
Upcoming sights to behold
Eclipses
The first-ever solar eclipse of 2021 is likely to June 10. This is an annular solar eclipse in which one may see a ring of fire. In India, it is likely to begin at 1:42 pm and end at 6:41 pm
Meteor showers
The Perseids are one of the brighter meteor showers of the year. They occur every year between July 17 and August 24 and tend to peak around August 9-13. In Hyderabad, they can be seen on the transcending night of August 12-13 between 11 pm and 5 am
Not a rare phenomenon
A sun halo is formed when light reflects from ice crystals high up in the atmosphere. According to the India Meteorological Department (IMD), this is not a celestial phenomenon but a meteorological one, just like rainbows. Halos require ice crystals to form — either from high cirrus clouds or free-falling crystals
Cloud watch
Unlike celestial events, meteorological ones cannot be predicted precisely. These simply present to us the nature of the atmosphere. There are over 100 varieties of clouds that paint the sky before and during the monsoon. Each one of them has a different property and are formed due to the changes in the atmosphere. The most common ones, ‘cumulus’ -- the fluffy, pearly white clouds -- have arrived in the city and are in plenty. Cumulus clouds indicate instability in the atmosphere and are a sign of rain. The amalgamation of multiple cumulus clouds form Nimbocumulus clouds (white-tipped grey clouds) or rain-giving clouds. These bring thunderstorms or pre-monsoon rains
— Mayank Tiwari mayank.tiwari@newindianexpress.com @out_in_doubt