Three suns in Sichuan — UFOs or sun dogs?

The above photo was snapped in Leshan, Sichuan Province, at around 8 in the evening on July 26. The photographer, Lu Shan, described the scene to the Tianshan Morning Post, which put the image on today’s front page:

He said that the unidentified luminous objects appeared in the west and seemed to the eye to be roughly 20-50 meters in diameter. For ten minutes, they moved at the slow speed of around 1 meter per minute from the southern part of the building to the north, decreasing in radius until they disappeared. “At the end, it was like a sunset. The light became warm like the setting sun.”

Observers called them UFOs, but one expert consulted by the newspaper suggested a natural explanation: a “sun dog” (幻日, also known as a parhelion), a halo around the sun caused by refraction of sunlight through atmospheric ice crystals, often looks like three suns hanging in the sky.

Yet sun dogs appear on the same vertical plane as the sun itself, not in the triangular configuration shown in the photo. Professor Wang Sichao of the Purple Mountain Observatory told the newspaper, “this phenomenon is fairly peculiar” and will require comparing other photographs before it can be confidently identified.

Update (2010.08.05): The newspaper, which went with more solar phenomena for its front page today (an assault from sunspots), has an uninformative update asking eyewitnesses to contact the observatory.