Documents / Case file
This CIA archives copy, released in 2026, holds Project Blue Book Special Report No. 14 (Analysis of Reports of Unidentified Aerial Objects). The Air Technical Intelligence Center at Wright-Patterson Air Force Base issued it on 5 May 1955. The study reduced about 4,000 sighting reports from 1947 to 1952 to IBM punched cards, with 3,201 cases charted, and applied chi square tests to compare known and unknown sightings. It concludes that it is highly improbable the reports represent technological developments beyond present-day scientific knowledge.
From the source:Release of 2026-06-12 This is the USAF Project Blue Book with a CIA cover sheet stating the document is "Official Record Copy." With the exception of the handwritten note on the first page, the content of this document has been available on CIA's public website.
“Harder”1 page
I IThe following points should be carefully noted about these histograms: ( 1) The negligible number of sightings when the sun is within I10° of the zenith and nadir (angle of elevation of the sun = ± 90 °) of the observer is due to the fact that the southern- most latitude of the U. S. is greater than the declination Iof the sun at the summer solstice, so that it would be im- possible for the sun to reach the zenith or nadir of any Iobserver in the U. S. (where most of the sightings were made). I(2) The time of day at which a particular angle of elevation of the sun occurs does not remain fixed but varies from Iday to day. Consider, for example, the variation in sunrise and sunset times over the course of a year. IThus, there are only two inferences to be made from this histogram: ( 1) the high peak of sightings soon after sunset, and (2) the lack of increase in the UNKNOWNS relative to the KNOWNS near either sunset or sunrise. IThis would seem to discount the possibility that atmospheric phenomena such as mock suns were the primary cause of the unknown reports, since Isuch phenomena usually occur when the sun is near the horizon. The Local Sun Time was computed as a step in the calculation of the Iangle of elevation of the sun. It is related to the hour angle by the equation: Local Sun Time (L. S. T.) =HA/15 + 12. 00, where L. S. T. is in hours and HA in degrees. I The cards were grouped on the basis of L. S. T. in intervals of one Ihour, and the number of cards in each interval was counted. Again the UNKNOWNS were sorted out and similarly treated. Histograms were con structed with the results of these tabulations of OBJECT SIGHTINGS I(Figure 41). Here, again, there is a peak in the early evening hours. IThe cards were then broken up into seven groups on the basis of the angle of elevation of the sun, as follows: IGroup 1 - Daylight sightings for which the sun was more than 10° above the horizon. IGroup 2 - Sunset sightings for which the sun was between 0° and 10° above the horizon. I Group 3 - Sunset sightings for which the sun was between 0° and 10° below the horizon. I Group 4 - Evening sightings for which the sun was between 10° and 40° below the horizon. I I58 I
Case file, from the pursue collection. The PDF is mirrored here; the original link is above. 312 pages are in the text index: search them above, or from the library's search.