The Tremonton Film Rangefinder: The Valley and the Rulers

THE TREMONTON FILM RANGEFINDER · 2 JULY 1952, 1110 MST
Thirty feet of 16 mm film, a 3 in lens, no reference point in the sky
Three laboratories measured angles; the objects' miles, mph and g are those angles times an assumed distance
the angles, the camera, the sun and the day's soundings are the record's
the range is a dial: every size, speed and g on the bench is recomputed from it
the object is a sphere drawn to be found, never a shape the film gives
turn the range · press play · switch the candidate · read the frames · open the file

Evidence

fact ⇄ what kind of claim · live

Newhouse, 11 August 1952: about 7 miles north of Tremonton on US 30S, 1110, a B&H Automaster with a 3 in telephoto lens at 16 frames per second, handheld; ten or twelve objects milling about; no reference point; one reversed course and the camera was held still for three or four passes

the witness's own letter and statement (D102 pp. 70, 113), the record card and the 28th Air Division interview (pp. 2, 6; D105 p. 31)

REPORTED

The angles: the Air Force lab's 2.1°/s ± 15 % for the single object's crossing (D102 p. 140); the Navy's December mean 0.1729 mm per frame, the same rate (p. 131); Baker's image diameters 0.0004 to 0.0016 rad and single-object rates 0.031 to 0.039 rad/s (p. 84); the sun at 64.5° / 131° (Naval Observatory, D105 p. 26)

what the film itself gives, measured three times; nothing on the bench changes them

MEASURED

The Navy's May 1953 report: three assumptions, five miles 'arbitrary', 3,780 mph per mm per frame, 2,457 and 378 mph, 965 g and 1,479 g, 98 and 16 ft, 'multiples of 12.5 approximately' (D098 pp. 7 to 8); Baker's distance table, 2.8 g at five miles (D102 p. 85)

the record's own arithmetic, quoted as printed and re-run beside it

REPORTED

A California gull's wingspan (1.22 to 1.37 m) and a herring gull's airspeed in flapping flight (12.8 m/s, about 29 mph); a B-29's span (141 ft); the Ogden radiosonde ascents of 2 July 1952 at 08:00 and 14:00 MST (IGRA); the 16 mm frame (10.26 × 7.49 mm, 40 frames per foot)

outside values, cited on the shelf; each is a dial where the bench uses it

MEASURED

The range (the one thing nobody measured), the exact angular size and rate within their measured brackets, the gull's speed and span, the aircraft's speed, which ascent, the camera's elevation

choices, shown as dials; every finding is quoted across their range

MODELLED

DOW-UAP-PR159 on the issued file: 1,117 blue-field frames at 24 fps, 386 of them light and 731 dark, no frame repeating its predecessor; the Air Force lab's sequence table runs the light sequences to frame 386 (D102 p. 142)

measured by this project on the transfer; the mapping to the 1952 film is a reading

MEASURED

Whether the film shows gulls a thousand feet off, pillow balloons, light sources five miles off, or something the record does not name

the one question this bench refuses to close for you

READING

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