|Miraged Sun, California
A much distorted setting sun caught by Kevin Baird near Palomar Airport, Carlsbad. ©Kevin Baird, shown with permission.
|The distortion was produced by refraction of the sunís rays through multiple temperature inversion layers. A single inversion has abnormally warmer air above cooler. Here inversion layers have stacked to produce a complex variation of temperature with height and a multiple sliced mock-mirage.
California is well known for these mirages, the result of air close to the ocean cooled by California Ocean Current and overlain by warm air from inland Utah and Nevada.
|Double and Triple suns?
Kevin Bairdís mirage above was well documented on several images. However, the Internet has recently been aglow with a video of a double sun sighting. The suns were well above the horizon and horizontally displaced. Why is this so improbable and almost certainly an artifact?
Firstly, significant deflection of the sunís rays by air layers at different temperatures requires long atmospheric path lengths and this only occurs when the sun is near the horizon. Secondly, temperatures change in the vertical direction and not horizontally. Horizontally displaced mirages need strongly tilted or even vertical slabs of different temperature air. This does not happen although slight tilting does occur for example when air is driven over mountain slopes.
It is easy to generate double and triple suns. Take photographs through windows. The ones at left were deliberately made by atmospheric optics expert Claudia Hinz (site) by shooting through the aircraft control tower windows.
Avoid looking through glass or using camera filters when photographing sky events, especially when the sun is in the frame. Is the event visible to the unaided eye, i.e. not through the camera viewfinder? Take several images while moving the camera between each one. Use a still camera in preference to video - the quality is much higher.
Doubtless there are very unusual mirages indeed. Strange sightings that do not fit our preconceptions should not be dismissed. But by their very nature they demand very exceptional care in recording and documentation to allow serious analysis.