Republic Of Korea, October 1959October 1959

A weather observer at Koon-Ni Range in South Korea watched a crescent-shaped silver object through a surveying telescope on the night of October 19, 1959. The object appeared to be about the size of the letter "c" on a penny held at arm's length. He tracked it for three hours and twenty minutes as it moved slowly toward the west, recording precise measurements of its position using a theodolite (a surveying instrument that measures angles and distances). During the observation, the object moved at a rate of approximately twelve degrees per hour, descending gradually toward the horizon.

Aircraft were scrambled to investigate the sighting, but the pilots found nothing in the area. Weather conditions were clear at the time of the observation.

The Air Force investigation focused on the object's movement and appearance. The observer's measurements showed the object moving westward at a rate matching the Earth's rotational velocity and the apparent movement of stars across the sky. The crescent shape and silver appearance, combined with the precise bearing and altitude data collected through the telescope, led investigators to conclude the observer had been watching the planet Venus. On that date and at that time, Venus occupied exactly the position reported, displayed a crescent phase when viewed through optical magnification, and set below the horizon after approximately three hours and twenty minutes, matching the duration of the sighting. The analysis noted that it is common for observers viewing Venus for the first time through a telescope to be surprised by its moon-like appearance with visible phases, since everyday experience suggests Venus appears as a star.

The full case file, comprising 12 pages as held by the National Archives microfilm T1206, Roll 37, is reproduced below.