Incident · 5 August 1952 · Over Tokyo Bay, northeast of Haneda AFB, Japan
Haneda AFB radar-visual sighting
Also known as Haneda 1952, Haneda AFB, Tokyo Bay 1952
Partly explained. Blue Book filed it as Unknown; the Condon Report (1969) judged the light most probably a bright star distorted by an optical effect, and the radar tracks anomalous propagation, without complete weather data. (source)
Late on 5 August 1952, control tower operators at Haneda Air Force Base in Tokyo watched a brilliant light over Tokyo Bay for about an hour, through binoculars a bright disc set in a larger dark round shape with smaller lights along its lower edge. Tachikawa's tower reported it too. The Tokyo GCI radar at Shiroi tracked a target in the area, orbiting, hovering and at one point splitting into three, and an F-94 night fighter vectored onto it held a radar contact for about 90 seconds before the target accelerated away. The fighter crew never saw it.
Far East Air Forces intelligence called it the first sighting in the Far East to combine visual and radar contact over an extended period, and Project Blue Book filed it as Unknown. The Condon Report later argued that the light was most probably a bright star, Capella, low on the horizon and distorted by an unusual optical effect, and that the radar returns were anomalous propagation, unconnected with the light; it conceded that complete weather data were not available.
Sources: Project Blue Book case file, U.S. National Archives (local copy) · Condon Report, Section III, Chapter 5 (1969)
Facts and claims
- documented At about 2330 local time on 5 August 1952, two airmen crossing the ramp to the Haneda AFB control tower saw an exceptionally bright light over Tokyo Bay to the northeast. With the two operators on duty, the four tower men watched it through 7×50 binoculars for about 50 minutes to an hour: a circular light of constant brilliance, part of a larger dark round shape about four times its diameter, with a smaller light and two or three dimmer ones along its lower edge. Source: doc-bluebook-haneda-1952.pdf
- documented Tower operator A/3C Lloyd West wrote that the object twice disappeared, seeming to travel east and climb “at a very fast speed, much faster than any jet”, and each time returned, “except for the last time when the jets were around. It seemed to know they were there.” He added: “I know it wasn't a star, weather balloons or Venus, because I compared it with all three.” Source: doc-bluebook-haneda-1952.pdf
- documented The control tower at Tachikawa Air Force Base, about 30 miles west, called Haneda at about 2350 about a brilliant white light over Tokyo Bay. The pilot of a C-54 entering Haneda traffic, asked to check, said it looked like a brilliant star and dismissed it. Source: doc-bluebook-haneda-1952.pdf
- documented The GCI radar at Shiroi (Site #4, 526th Aircraft Control and Warning Group) picked up a target in the reported position: its controller, 1st Lt. Henry E. Albert, tracked it in a right orbit at a rough 100–150 knots, stopping and hovering at times and reaching perhaps 250–300 knots; at about 0012 it broke into three smaller contacts about a quarter-mile apart. He called it “a bona-fide moving target”, though weaker than a single jet fighter. Source: doc-bluebook-haneda-1952.pdf
- documented An F-94 of the 35th Fighter-Interceptor Wing (1st Lt. Wesley R. Holder, pilot; 1st Lt. Aaron Jones, radar operator), airborne at 0003, was vectored onto the GCI target and made a weak but distinct radar contact at 6,000 yards; as Jones called for a hard right turn, the target appeared to accelerate suddenly and left the scope after about 90 seconds. The crew saw nothing, despite exceptional visibility; Jones, with about seven years' experience of airborne radar, said it was a bona-fide target. Source: doc-bluebook-haneda-1952.pdf
- documented Project Blue Book's record card marks the case “Unknown”; a later note in the file says the radar reports allow no plausible explanation and that, without weather data by height, anomalous propagation cannot be estimated. Source: Project Blue Book case file: Haneda AFB, Japan, August 1952
- documented The Condon Report (Section III, Chapter 5, case 237-B) concluded: “the most probable causes of this UFO report are an optical effect on a bright light source that produced the visual sighting and unusual radar propagation effects that produced the apparent UFO tracks on radar.” It proposed the star Capella, 8° above the horizon at 37° azimuth at midnight, as the most likely light source, and argued that the visual object and the radar target were not the same, since the light was still seen after the F-94's radar showed the target leaving. Source: files.ncas.org (archived)
Connected files
Documents
- Project Blue Book case file: Haneda AFB, Japan, August 1952 (documented in)
Programs
- Project Blue Book (investigated by) — Blue Book's record card marks the conclusion “Unknown”
Mentioned in this file
- National Archives and Records Administration (Organization)