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CASE FILE D-98

Navy Analysts Ran a 1952 UFO Film Frame by Frame. Birds, Aircraft and Balloons Ruled Out - Case D-98

2026-09-12 · Declassified UAP records
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On 4 May 1953 the Officer in Charge of the U.S. Naval Photographic Interpretation Center sent the Director of Naval Intelligence a report on "movies of unidentified objects taken in Utah, 2 July 1952" - "approximately 30 feet of processed, 16mm color motion picture film" - together with "additional movies taken in Montana, 1950." The request had come from the U.S. Air Force, and the report states that its findings "do not necessarily represent the official attitude of the Department of the Navy."

The Center's Photogrammetry Division projected the film frame by frame at 22 times magnification, plotted the objects' positions, measured brightness with a densitometer, and computed speeds at 16 frames per second. Every size and speed rests on an assumption the report itself calls "arbitrary": that the objects were five miles from the camera. On that basis the objects were "oblate or disk shaped," between 16 and 98 feet across, with Utah speeds of 378 to 2,457 mph, a maximum acceleration of 965 g and a maximum deceleration of 1,479 g.

"It is the majority opinion of the group conducting this analysis that these images are light sources" which they were "not able to identify in terms of natural phenomena or commonly known man-made objects." "For the same reasons, birds, aircraft and balloons are ruled out." Outside experts in astronomy and physics were shown the data and "were not able to recognize these objects as man-made," but the report notes that "no attempt was made to corroborate the opinions presented" and that "because of the lack of proper equipment, money and personnel, the investigation was limited."

Outside context, not in this document: the Utah film of 2 July 1952 is widely known as the Tremonton film. In January 1953 the scientific panel convened by the CIA and chaired by H. P. Robertson reviewed it and attributed the objects to seagulls reflecting sunlight - the opposite of the Navy analysts' view. The Navy report is transcribed in full below.

The Document

CONFIDENTIAL - SECURITY INFORMATION (declassified - authority NND 67905) 4 May 1953

Naval Photographic Interpretation Center Report - Interpretation of Movies of Unidentified Objects (4 May 1953)

Bureau of Aeronautics Route Sheet (cover)

BUAER ROUTE SHEET, NAVAER-141A (REV. 5-52), marked CONFIDENTIAL - SECURITY INFORMATION. Handwritten routing to the Photographic division (PH) and additional routings (PH-5, PH-431, PH-4), with dates in May and June. The reverse (comments) side is blank except for a received stamp: "BUREAU OF AERONAUTICS NAVY DEPARTMENT RECEIVED 1953 MAY 14 AM 8 15". Stamped "REVIEWED BY NAVAIR DECLASS PROJECT ON 10/4/07 - DECLASS IN FULL PER EO 12958 - OTHER EQUITIES: YES".

U.S. Naval Photographic Interpretation Center - Interpretation of Movies of Unidentified Objects; progress report on (4 May 1953)

1. Reference (a) is a request from U. S. Air Force for the interpretation of movies of unidentified objects taken in Utah, 2 July 1952. Included among the enclosures are approximately 30 feet of processed, 16mm color motion picture film and a list of questions for guidance in determining the type of analysis desired. Reference (b) requested interpretation of additional movies taken in Montana, 1950. This report supercedes reference (c) and presents the test procedures and methods designed to answer the questions contained in enclosure 7 of reference (a). The results and analysis were performed by the Photogrammetry Division, Evaluation Department of this Center and do not necessarily represent the official attitude of the Department of the Navy or this Center.

2. Tests and Procedure

a. Plots.

The film exposed in Utah is in very poor condition; dry, brittle, and with a tendency to break. After initial viewing, duplication of the film was performed in order to preserve the film. In the duplication process some color correction was made to permit better viewing of the objects. To prepare plots of the objects, a stop frame projector was rigidly mounted at a fixed distance from a finely-ground glass screen. The magnification was 22 times giving a format size of 14.2" wide. This proved very satisfactory and provided a shadow free image upon which overlay plots could be made.

A preliminary detailed study of the Utah film was made and it was decided that:

For convenience in interpretation, the film was divided into three parts, each part being considered an entity. Part I consisted of the footage taken at f8; Part II, the footage taken at f16 with a panning motion; and Part III, the footage taken at f16 during which the camera was held steady. Three definite groups of lights were observed throughout the film and plots were recorded as follows:

TABLE I - PLOTS OF POSITIONS

b. Densitometric tests:

Densitometric data were obtained with a Densichron, Model 2150 manufactured by the Welch Scientific Company. The Densichron has a scale range of 0-3. The procedure was to project each frame at approximately 22 times magnification onto a finely-grained-glass screen. The background (sky) was then measured at several places and the density set to 3.0 (variations in background densities were in the order of 0.02 and were regarded as uniform). A set of three readings were made of each of seven objects in Part I, and of the single object in Part III of the Utah Film. Readings were made of the entire Montana film.

Enclosure (8a and 8b) are graphs of the density readings obtained of the two lower groups of objects in frames 1-129 of the Utah film. Enclosure (9) is a density graph of the single object (94 frames) in Part III. Enclosure (10) is a graph where six successive Densichron readings were averaged and advanced one reading each determinant.

Of the Montana film, densities were plotted as above and are enclosures (11) and (12).

The results of the density readings may be questioned in that these objects varied in size so that at the minimum sizes the densichron probe was measuring the entire object, and at the maximum size the probe was measuring only a portion of the objects. Because of this situation only the largest readings obtained by scanning the objects were used. It is understood that normal procedure would be to read the entire object. This was impossible with the equipment on hand.

In addition the film, with which this investigation was conducted, is a duplicate of a copy. This raises the question as to whether the central portion of the objects were burnt out during the duplication processing. Density readings were made to compare the clear areas and the objects. It was found that the minimum difference is 0.4. This indicates that relative luminosity may still be obtained with the procedure used. Concurrent with the density readings, relative sizes of the objects were noted in order to correlate distance and luminosity. Enclosure (13) is a plot of the same object wherein the relationship of distance and luminosity can be detected in Utah film.

3. Answers to Questions

Answers keyed to the questions contained in enclosure (7) of reference (a) are hereby presented. They supercede those contained in reference (c) and present the final analysis as requested.

1. Analysis of the graph correlating luminosity and size indicate that as the luminosity of the objects increase, the size is larger also. This could be the effect of viewing directly, a reflecting surface. This is considered not probable because of the length of time they were viewed continuously on the film, approximately 90 seconds, and because of the angle through which they were photographed, approximately 60 degrees.

It is felt that if these images are reflective surfaces, blinking would occur during a period of 90 seconds while passing through an angle of 60 degrees when photographed at the rate of 16 frames per second. This premise would permit highly reflective balloons or spheroids to be a possibility. However, the velocity and acceleration computations (sub paragraph 8) rule this possibility out. It appears, therefore, that if these objects are a reflecting surface, they are of a design, speed, and power not commonly known. The velocity and acceleration attributed to the objects may be caused by light reflected off a highly reflective surface onto an atomospheric screen where a slight angular turn of the reflective surface would appear as high acceleration. This possibility is considered not probable because of the sun angle and atmospheric condition reported at the time of photography and because of the variations in luminosity which, under the above conditions would remain constant.

It is the majority opinion of the group conducting this analysis that these images are light sources. This will explain the non-blinking and variations in luminosity - but not the velocity or acceleration factors. In either case, light source or reflective surface, it appears as if the objects are of a nature which we are not able to identify in terms of natural phenomena or commonly known man-made objects.

2. There is no indication of what kind of objects could have caused the images except that they must be of a construction, design, and material not commonly known. This is indicated by the computed acceleration rate and elocity (answer 8). For the same reasons, birds, aircraft and balloons are ruled out.

3. An analysis of the charts relative to movement indicate that there were group and individual movement. Within a group it appears as if the individual objects were moving counter-clock-wise along an elliptical or similar track. Thus when two objects crossed the camera line of sight they will appear to fuse into one. As they continued along their paths it will appear as if one object became two. This occured at reglar intervals at approximately every 25th frame as plotted in charts 5a and 5b.

4. All objects appear to have the same characteristics in regards to shape, color, size and relative motion.

5. The shape of the objects appears to be oblate or disk shaped, color; blue-white, and maximum and minimum size; 98 and 16 feet. The size is based on the assumption that the objects are five miles from the observer.

6. Fade in and fade out of the objects were analyzed as in 3 above. In this case the group movement was such that the distance between the objects and camera was increased so that the objects could not be recorded on the film thereby causing the apparent fade-out. Fade-in as attributed to a shortening of the distance from the fade-out area to the camera station.

7. Plots of the groups indicate that the objects move counter-clock-wise relative to the axis of flight path. However, nothing has been detected which indicates motion of the individual objects about their own axis although this motion appears to be likely.

8. In determining the velocity of the objects three assumptions were made:

It is obvious that (b) is a fallacy; however, this assumption will give the minimum velocity and the actual velocity is greater than computed. The assumption that the objects are five miles from the camera is an arbitrary one. However, based on the emulsion speed and focal length, an object 50 feet in diameter and five miles from the camera will be recorded on the film with sufficient resolution to identify major details of the object. It is felt that if these objects were closer than five miles at the time of recording, details would appear on the film.

Velocity is computed to be 3780 mph for a shift of 1 mm per frame if the object is five miles from the observer. From 55 measurements taken from Part III of the Utah film, the maximum and minimum velocities were 2457 and 378 mph respectively. These figures differ from those given in reference (c) and were computed from measurements obtained under more controlled conditions. Acceleration was determined from the formula:

Since "g" is equal to 32.17 ft/sec2 it was computed that:

Velocity and acceleration determinations were also made from the Montana film. In this case, terrestial objects appeared in the film and were held to as control. Subsequently, the velocity and acceleration determinations are considered to be more reliable. On the assumption of (b) and (c) above the maximum and minimum velocities of the left object are 1374 and 361 mph respectfully. For the right object they are 1117 and 189 mph. Accelerations were computed as:

The above determinations were made from a total of 322 measurements. It was noted that the acceleration and determinations were in multiples of 12.5 approximately. This may be of significance although no study has been conducted to determine this.

9. Velocity and acceleration were treated in sub-paragraph 8 above. Paragraph 2a indicates the controls used during this investigation.

10.

4. Discussion

During the study and investigation of the unidentified objects, the preliminary data uncovered were revealed to experts (with proper security clearance) in the fields of astronomy and physics. Although they presented certain natural phenomena theories to explain the cause of the objects under certain conditions they were not able to do so under the conditions during which the photography was taken, nor were they able to recognize these objects as man-made.

As to the results of the investigations being reported, no attempt was made to corroborate the opinions presented. Because of the lack of proper equipment, money and personnel, the investigation was limited. There are obvious tests which can be conducted to prove or disprove some of the findings presented. It is suggested that these be undertaken.

5. Reference (d) requests spectrophotometric analysis of the Utah film be made. Preliminary plan of test is underway.

L. W. KEITH (signed)

Enclosures - Charts

The remaining pages of the file are the hand-drawn enclosures referenced in the report, each stamped CONFIDENTIAL SECURITY INFORMATION: overlay plots of object positions and tracks (including sheets labeled Enclosure 2, Enclosure 3 and Enclosure 5b) and graphs headed "DENSITY READINGS" and "AVERAGE OF DENSITY READINGS" for the Utah and Montana films. The charts carry only axis labels, legends and short notes; no additional narrative text.

Released in the PURSUE disclosure. Stamped "Reviewed by NAVAIR Declass Project" on 10/4/07, "Declass in full per EO 12958". The 23-page file is a Bureau of Aeronautics route sheet, the 7-page report, and the hand-drawn chart enclosures. No redactions. · U.S. Naval Photographic Interpretation Center, U.S. Naval Receiving Station, Washington, D.C., to the Director of Naval Intelligence; copy routed to the Bureau of Aeronautics (DoW-UAP-D098)

Where It Happened

Full Transcript

July 1952. In Utah, someone films unidentified objects on sixteen millimeter color film. The Air Force asks the Navy to analyze it.

The Naval Photographic Interpretation Center received about thirty feet of that film, and later a second film, shot in Montana in 1950.

Its analysts projected the film frame by frame, magnified twenty two times, plotted every position, measured brightness, and computed speeds. To do it, they had to assume the objects were five miles away.

On that assumption, the objects were oblate or disk shaped, sixteen to ninety eight feet across.

And the computed motion: speeds up to about two thousand four hundred fifty miles an hour, and accelerations up to nine hundred sixty five g.

The majority opinion: light sources they could not identify as natural phenomena or known man-made objects. Birds, aircraft and balloons, ruled out.

The report admits no one corroborated those opinions, and the study was limited by a lack of equipment, money and personnel. And in January 1953, a C.I.A. convened panel had already reviewed the Utah film, and suggested seagulls.

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Sources

All documents and footage are authentic, public-domain U.S. government releases. Narration is AI-generated text-to-speech.