|Strange Lights over Kiev, Ukraine Imaged by Roman Yagodka on September 19, '09. "I noticed the phenomenon at approximately 1am and started to take pictures. After that it just slowly faded away as the cloud moved from the left to the right. At, say, 1:20am it was completely gone."
©Roman Yagodka, shown with permission.
|These are unshielded city lights being reflected by plate shaped ice crystals in the thin clouds. Normally the reflections form a pillar shape but these ones are quite localised indicating perhaps that the crystals were aligned nearly horizontal without any significant range of tilts and in a thin layer.
Roman estimated the heights of the crystals. He knew the sources of the lights. At left the lights were from a huge array (600x600m) of greenhouses 26km distant. A smaller array of greenhouses (500x300m) 20km distant produced the central light. The multiple reflections at right were from the lights of an airport 29km distant. He assumed that the reflecting crystals were roughly half way between the lights and the camera. The stars help determine the angular scales of the image. At right is Aldebaran in Taurus, Capella in Auriga is at top centre and the Pleiades are just below ‘Galleries’.
The calculated cloud heights were 4-4.5km (13 to 15,000 ft) – perhaps altostratus or unusually low cirrus and both known to contain ice crystals. The ground temperature was a relatively warm +10C. The lights are unusual because artificial light pillars are better known in subzero temperature weather when the reflecting crystals are in lower ice fog.