Sun halo draws eyes to sky Published: June 16, 2005 Seen through the 14mm lens of a Canon EOS1-D, the sun halo shines brilliantly Wednesday afternoon above the downtown Mac skyline. Tom Ballard/News-Register By BETHANY MONROE Of the News-Register Postal Service employee Jim Schmechel was going about his usual delivery routine on Wednesday when he noticed a strange phenomenon in a clear, blue sky. "It looked like the opposite of a rainbow arc," Schmechel said. Taking a closer look, he realized a bright ring had come to encircle the sun. The spectacle, witnessed by many residents, is called a sun halo, according to John Day, a retired meteorologist, author and physics professor who writes a weather column for the News-Register. A sun halo is similar to a rainbow, but it is caused by sunlight hitting ice crystals rather than raindrops, Day said. He said the crystals are found in cirrostratus formations. The cirrostratus is a near-transparent, veil-like cloud that sometimes become visible only when it creates a halo around the sun or moon, Day said. Therefore, halos can occur on seemingly cloudless days. A halo forms when the light bounces off ice crystals at an angle, creating a prism effect. Often, the halo appears to be bright white, but sometimes other colors are visible as well, giving it a rainbow look. Although Schmechel had noticed rings around the sun in the past, he said Wednesday's halo was the most prominent he'd ever seen. "I just thought it was really unusual, especially with such a clear day," he said. Sun halos can signal a coming storm, Day said, but that's not always the case. He estimates halos appear in the sky about 25 times a year. "They are not common," he said, "but they are not extremely rare."