Udine, Italy, July 1958July 1958

Starting in July 1958, residents of Udine, Italy, began reporting sightings of a mysterious luminous object moving across the sky. The object appeared repeatedly, sometimes multiple times per week, and drew the attention of local astronomers, newspaper reporters, and everyday citizens. An Italian newspaper article translated in the Air Force file describes the object as a "firefly," a nickname locals had given it. Photographs were taken. In one particularly notable sighting on August 19, a squadron of Italian jet planes attempted to chase the object.

Amateur astronomers in the area conducted trigonometric calculations based on photographs taken from multiple locations and concluded the object was traveling at approximately 16,500 kilometers per hour at a height of about 150 kilometers. The object exhibited distinctive behavior: it moved across the sky from different directions at different times, showed irregular zig-zag motions, rotated on its axis, and spiraled through the atmosphere. Professor Dino di Colbertaldo, a teacher from Milan University who was in the region, observed the object repeatedly. He noted that it appeared on a regular schedule, advancing 12 minutes each night, and followed an identical path each time it was sighted.

The Air Force evaluated this case as "probably satellite." An internal comment on the case record notes that the motion and description of the object were consistent with satellite observations, and that repeated sightings indicated the witnesses were seeing the same object on different occasions. However, the Air Force also observed that without precise timing data and detailed tracking information, a specific identification could not be made with certainty. Photographs were reportedly taken during the sightings but were not forwarded with the report to Air Force headquarters.

The full case file, containing 17 pages, is reproduced below as held by the National Archives.