|Bottlinger's Rings ~ Tim Stone (Tim's Pix) pictured this very rare sight from 32,000 ft over Northwest Illinois March 23, 2010.
“.. I was (of course) watching for atoptics, and saw a brilliant subsun. That's actually not too unusual, but as I was taking pictures a ring developed around it. The ring appears in three of my frames [right]. As that particular cloud bank fell behind us, the subsun then resumed its usual appearance.” All images are without enhancement from the original camera RAW files.
©Tim Stone, shown with permission.
A subsun is a familiar sight beneath an aircraft. It is a blindingly bright reflection sunlight from flat-plate ice crystals in altocumulus cloud.
This is different. Bottlinger’s rings - delicate and shimmering ovals around the subsun - are an unusual sighting. They are ephemeral and might last for no more than a few seconds. Tim’s images show two main rings 3.1 and 5.4° across their narrow axes with less distinct glows.
Bottlinger’s rings are poorly understood. Pyramidal crystals with sides sloping only 1-3° might make them. The rings are probably related to the small elliptical halos sometimes seen around the sun.
The HaloSim ray tracing is for the sun elevation of ~31° and uses the crystal at top right. The second ring B is from direct mirroring by the pyramid facets. The inner ring A comes from internal reflections. Quite surprising ray routes generate bright patches above and below the subsun.