Effect glow, Uzbekistan. Photograph
by Eva Seidenfaden (Atmospheric
optics site) - " .. taken on the 17th of September
about half an hour after takeoff from Tashkent at 15.30 local time.
The yellow spot kept following the plane, but eventually vanished
behind it because we were flying from the east to the west.
There was no water in the air, nor ice crystals, just dust and sand."
towards the antisolar point for this very subtle glow drifting across
the landscape as the aircraft flies onwards.
It is slightly yellow because of the absence of shadows. Shadows are
bluish because they are lit predominantly by blue skylight.
are other antisolar brightenings but they need water droplets. An
afternoon glow in a desert is a fairly sure sign that the opposition
effect is operating.