At about 19:00 local time on 28 September 1952, an American airman returning to an operations building on Tsushima noticed a deep-red light above the horizon. Two colleagues also watched it, including through low-powered binoculars. They described a change towards orange and an eventual disappearance below the horizon. An F-94 was directed towards the area, but did not identify the light.
The released record contains an official report, three personal statements and the appraising officer’s explanation. That officer identified the object as Mars and attributed its apparent descent to refraction at low elevation. The original observations, however, include differences in the stated direction and height. UKPX treats the planetary identification as a possible explanation, retaining both the reasoning and its limitations.
A light first taken for a star
Airman Warren D. Groverstein’s statement in the four-page original file places the first observation at roughly 19:00. He initially thought the object was a star and continued into the operations building. About five minutes later Airman Carlton L. Hall mentioned a strange object outside. The two went out and tried to identify it with binoculars.
Groverstein described a colour change from deep red to light orange. At first the light seemed stationary, later appearing to move farther away and lower towards the horizon. His account estimates an initial height of about 25 degrees, followed by a position near 10 degrees and then disappearance in roughly four minutes. These are estimates by an observer watching a distant light; the statement does not describe instrumentally measured angles.
He also estimated a distance of about ten miles and a general direction near 240 degrees. Without a known physical size or independent range measurement, the distance remains an estimate. It cannot be combined with the angular impression to calculate a reliable object speed, height or size. The record’s comparison with a star is a description of appearance, not proof that the observer had established an astronomical distance.
What the other two airmen reported
Hall’s statement begins around 19:05, when he looked through the operations building’s window and saw a reddish light. Groverstein told him he had seen it earlier but had thought it a star. Hall joined the binocular observation, reported the red-to-orange change, then went inside to notify the crew chief and detachment commander. On returning outside he watched the light approach the horizon for about four minutes.
Hall briefly considered a reflection from the Sun, but rejected that idea because the Sun had already set. That is part of his own attempt at interpretation, rather than an independently tested reflection hypothesis. His account does not identify a vehicle, describe a detailed structure or report a sound. It records an unfamiliar light whose appearance he could not resolve.
Airman John F. Vanderpool said Hall and Groverstein called him outside at approximately 19:10. He watched through binoculars and described a dark-red object changing towards orange. His statement places it about ten degrees above the horizon in the same general direction. He went back inside to contact the control organisation; when he returned, the light was gone. His statement therefore supports the later stage of the observation, rather than independently confirming the entire earlier sequence.
What the formal report did and did not establish
Air Intelligence Information Report IR-4-52 was prepared on 11 October, using information dated 28 September. Its summary explicitly says the sighting is being forwarded for information and has not been evaluated by that headquarters. This distinction matters: collecting an account within an intelligence channel is not the same as endorsing its interpretation or declaring an unknown aircraft present.
The report describes one circular, star-sized object, seen with unaided vision and four-power binoculars at Tatsuta Saki. It records no sound, no physical evidence and no radar pickup. The witnesses were regarded as reliable, but the file does not contain a photograph or a measured track. Reliability supports taking their reports seriously; it does not supply the missing range and angle measurements.
An F-94 was vectored towards the area. The formal report says the light disappeared before an interception could be made, while Groverstein adds that the aircraft did not approach the correct observed area. Neither version establishes a successful close examination. In particular, sending a radar-equipped interceptor does not create a positive radar detection where the report expressly records none.
The officer’s Mars comparison
The final report page contains the appraising officer’s comments. It places Mars at an azimuth of about 255 degrees and an elevation of roughly ten degrees at 19:00 local time. The officer considered the circumstances suitable for Mars to produce the observed appearance and proposed low-angle atmospheric refraction as the reason for the perceived downward movement.
That explanation has a specific evidential basis: a named astronomical object, an estimated direction and elevation, the observation time and the sunset setting. It is more informative than a generic suggestion that any unexplained point must have been a star. The summary card accordingly places the case in its astronomical classification and repeats the Mars interpretation.
There are still qualifications in the underlying account. The witness bearing is about 240 degrees rather than 255, and Groverstein’s earliest height estimate is greater than the officer’s ten-degree comparison. The file does not provide a fresh observational reconstruction demonstrating how refraction produced the full reported change. Those discrepancies need not rule out an imperfectly estimated planet sighting, but they should not be silently removed to make the identification exact.
Reading the surviving record
The documented evidence is a short visual observation, three overlapping accounts and a subsequent astronomical assessment. The sources do not support a claim of a radar-tracked craft, an interception, several luminous objects or a close view of a disc. Even the word “circular” in the formal description should not be inflated into a resolved saucer shape when the same document compares the apparent size with a star.
A red light does not automatically establish an orb-shaped craft, and a colour change need not mean that a light was flashing. The article preserves what observers described while distinguishing their impressions from a demonstrated object identity. The possible-explanation assessment refers to the original Mars interpretation, rather than a new astronomical calculation by UKPX.
Location and document image
The map is a broad Tsushima Island reference, rounded from the checked gazetteer coordinates. It does not identify the historical Tatsuta Saki station, reconstruct the light’s position or mark an accessible viewing site. A former military location cannot be treated as a visitor destination merely because a report gives it a name.
The lead image is the original Blue Book summary card, reproduced from the public-domain United States government file. It is not an encounter photograph. All four pages were reviewed, including the separate statements and the final appraisal, so that the short card label can be read against the fuller evidence that produced it.