Sighting of Unusual Phenomenon on Horizon Near Iranian/USSR Border

On June 17, 1966, at 2147 hours local time, the crew of an international flight approaching the Rudashur beacon, approximately 25 miles southwest of Mehrabad Airport in Teheran, Iran, observed an unusual phenomenon on the horizon. The object was described as a brilliant white sphere, initially appearing three times the size of a full moon and possessing the coloration and intensity of a full bright moon. At the time of the sighting, the aircraft was flying at an altitude of 18,000 feet on a course of 070 degrees at a speed of approximately 200 knots. The crew was preparing to fly a circular pattern over the Rudashur beacon prior to descending for landing. The witness estimated the duration of the sighting to be four to five minutes. The witness further estimated the position of the sphere to be on a heading of 010 degrees, deep within the Soviet Union, perhaps north of 60 degrees latitude. Throughout the observation, the sphere grew in size until it appeared to fill the sky, while its intensity diminished. The base of the sphere appeared to rest on the horizon, and the center of the sphere was observed to be rising during the period of expansion. Weather conditions were reported as excellent with unlimited visibility. A second airliner, flying at a slightly lower altitude, also observed the phenomenon. Upon landing at Mehrabad Airport approximately 20 minutes later, the crew discovered that the phenomenon had not been observed from the ground, except possibly during its final stages, at which point its intensity had diminished to the extent that it would have gone unnoticed.