Pics: Rare Sun Halo Sighted In Dehradun Share On Sunday, a rainbow-colored sun halo was seen here. Residents captured the sight on their smartphones and uploaded it to social media. Rare optic phenomena, the sun-halo (or ’22 degree’ halo) appears as a rainbow around the sun and moon with a radius approximately 22 degrees. This happens because sunlight is reflecting off millions of hexagonal crystals suspended in atmosphere. Director Meteorological Centre Bikram Sin said.See alsoNewsPeraribalan, convicted of assassination of Rajiv Gandhi, walks freely 31 years later (Except for headlines, the story is not edited by Bibarud staff.