September 25, 2015
A 22° halo was seen around the sun today afternoon. No special equipment was needed to see it. People all over the city witnessed the phenomenon.
According to experts, halos are optical phenomenon produced by light interacting with ice crystals suspended in the atmosphere, resulting in a wide variety of coloured or white rings, arcs, and spots in the sky, around the source of light. These halos are indications of high thin cirrus clouds that are drifting 20,000 feet or more above ground level.
These clouds contain millions of tiny ice crystals. When light travels through these crystals, both refraction (splitting of light) and reflection (glints of light from these ice crystals) occur. The crystals have to be oriented and positioned just so with respect to your eye, in order for the halo to appear.
Among the most well known halo types are the circular halo (properly called the 22° halo), light pillars, and sun dogs, but there are many more; some are fairly common, while others, rare.