Sighting of Unusual Phenomenon on Horizon Near Iranian/USSR Border

This Central Intelligence Agency Information Report details a sighting of an unusual aerial phenomenon reported on June 17, 1966, near the Iranian/USSR border. The primary witness, an airline pilot with over 20 years of flight experience, was operating an international flight approaching Mehrabad Airport in Teheran, Iran. At approximately 2142 hours local time, while flying at 18,000 feet with a heading of 070 degrees and a speed of 200 knots, the pilot observed a brilliant white sphere on the horizon near the Rudasher beacon. The object appeared suddenly and was estimated to be three times the size of a full moon. The pilot noted that the sphere appeared to be in a circular pattern over the beacon before descending to a lower altitude. Over the course of four to five minutes, the object grew in size while its intensity diminished, eventually appearing to fill the sky. The witness estimated the object's position to be deep within the Soviet Union, at approximately 60 degrees latitude. The weather conditions were described as excellent with unlimited visibility. A second airliner at a lower altitude also observed the phenomenon and discussed it with the primary witness; however, the object was not visible from the ground, likely due to the high mountain range north of the city. In his assessment, the pilot stated he had never seen anything similar in his career. He offered two theories: that the object was a 'false moon' similar to a phenomenon previously reported near Rome, Italy, or that it was caused by gases from a man-made explosion, which were illuminated by the sun from behind.