DULUTH, MINN., August 1952August 1952

On August 7, 1952, a U.S. Weather Bureau meteorologist stationed at Duluth, Minnesota spotted something unexpected while tracking a weather balloon through a theodolite (a surveying telescope used to measure the position of high-altitude objects). At approximately 1506 (3:06 p.m.) local time, a small, bright light appeared in his field of view. The observer described it as resembling a bright spot of sunlight, with dimensions of about 1/20 of an inch long and half that in height when viewed through the theodolite.

The observer watched the object for roughly two minutes. The light showed no movement and remained at the same angle: 237.3 degrees azimuth (a compass bearing roughly southwest) and 22 degrees elevation above the horizon. The light was shimmering and bright but not so intense that its edges could be clearly defined. The observer saw no sound and detected no motion at all while the light was centered in the theodolite's field of view.

The meteorologist then adjusted his theodolite to check on the pilot balloon (the weather balloon). When he moved the instrument back to where the light had been, he could no longer locate it. The observer was confident the light was real and not a flaw in the instrument itself, noting that moving the theodolite had caused the light's apparent position to shift across his field of view. He offered no conclusion about what the object was, whether it reflected light from something else or generated its own light, or how far away it might have been.

The Air Force file notes that the observer was considered "reasonably reliable" and that there was no physical evidence, no attempted interception, and no identification of the object. The case remains listed as unknown.

The full case file, as reproduced below and held by the National Archives, comprises 12 pages.