Original Item: Only One Available. This is a World War Two United States Army Air Force unissued finder height photo interpreter Type C-1 manufactured by Advertising Displays Inc of Covington, Kentucky. The top of the box reads:

Finder, Height (Photo Interpreter's)
Type C-1
Property, U.S Army Air Forces

The box container measures 7 1/2" x 5" x 2 1/2".  Included are original instructions and two envelopes containing spare parts.

One envelope reads:
Part #     Nomenclature         Qty
HF-121    SLIDE Y MOVEMENT    1
HF-120    SLIDE X MOVEMENT        1
HF-130     SCALE             1

The other unopened envelope reads:
Part #    Nomenclature        Qty
HF-108    SPRING LOCK ASSY    1
HF-135    MIRROR            1
HF-136     CLIP MIRROR        1
HF-139    PIN TAKE UP        1
HF-140     SPRING TAKE UP        1
HF-145     SPRING X MOVEMENT    1
HF-148     SCREW 2-56 X 3/16 FLT HEAD

There is also a second set of folding views held in USAAF marked envelope.
The collection and interpretation of aerial reconnaissance intelligence became a considerable enterprise during the war. Beginning in 1941, RAF Medmenham was the main interpretation centre for photographic reconnaissance operations in the European and Mediterranean theatres. The Central Interpretation Unit (CIU) was later amalgamated with the Bomber Command Damage Assessment Section and the Night Photographic Interpretation Section of No 3 Photographic Reconnaissance Unit, RAF Oakington, in 1942.[18]

During 1942 and 1943, the CIU gradually expanded and was involved in the planning stages of practically every operation of the war, and in every aspect of intelligence. In 1945, daily intake of material averaged 25,000 negatives and 60,000 prints. Thirty-six million prints were made during the war. By VE-day, the print library, which documented and stored worldwide cover, held 5,000,000 prints from which 40,000 reports had been produced.[18]

American personnel had for some time formed an increasing part of the CIU and on 1 May 1944 this was finally recognised by changing the title of the unit to the Allied Central Interpretation Unit (ACIU). There were then over 1,700 personnel on the unit's strength. A large number of photographic interpreters were recruited from the Hollywood Film Studios including Xavier Atencio. Two renowned archaeologists also worked there as interpreters: Dorothy Garrod, the first woman to hold an Oxbridge Chair, and Glyn Daniel, who went on to gain popular acclaim as the host of the television game show Animal, Vegetable or Mineral.

Sidney Cotton's aerial photographs were far ahead of their time. Together with other members of his reconnaissance squadron, he pioneered the technique of high-altitude, high-speed photography that was instrumental in revealing the locations of many crucial military and intelligence targets. Cotton also worked on ideas such as a prototype specialist reconnaissance aircraft and further refinements of photographic equipment. At its peak, British reconnaissance flights yielded 50,000 images per day to interpret.

Of particular significance in the success of the work of Medmenham was the use of stereoscopic images, using a between plate overlap of exactly 60%. Despite initial scepticism about the possibility of German rocket development, stereoscopic analysis proved its existence and major operations, including the 1943 offensives against the V-2 rocket development plant at Peenemünde, were made possible by work carried out at Medmenham. Later offensives were also made against potential launch sites at Wizernes and 96 other launch sites in northern France.

Particularly important sites were measured, from the images, using Swiss stereoautograph machines made by Wild (Heerbrugg) and physical models made to facilitate understanding of what was there or what it was for.

It is claimed that Medmanham's greatest operational success was Operation Crossbow which, from 23 December 1943, destroyed the V-1 infrastructure in northern France. According to R.V. Jones, photographs were used to establish the size and the characteristic launching mechanisms for both the V-1 flying bomb and the V-2 rocket.