Ross Williamson-projector stereoscopic maps, type SP3 A gem for enthusiasts and collectors alike, this is a rare and unique example of a projector Ross Williamson. It was one of the 3 or 7 units connected to a Multiplex-Ross SP-3 stereo projector. The complete set consists of projectors, which represent replicas miniature cameras aircraft, mounted on a beam supported at a height above the appropriate table plotting. This unit stereoscopic projection was designed in 1948 and was used for photogrammetric purposes (interpretation of aerial photographs) from 1949 to the 1970s. a 3D image of a landscape created on a perfectly flat surface simultaneously overlaying slide projections 6x6 cm in each of the projectors in a single image. The slides were glass plates on a diapositivo of the original aerial photograph was printed. Based on these projections, detailed survey maps were drawn artillery for many years before the advent of digital mapping. This projector particular was produced by the Williamson Manufacturing Company of London, recognized for its co-development and production of the vast majority of aerial cameras and installed cannon on RAF aircraft from World War One to the period the Second World War. All moving parts of this projector are fully functional. Ross lens and all glass components are in excellent condition and the enamel paint the entire unit. Detachable housing condenser is not equipped with a lamp or coolant hose. This projector could, if desired, continue to be used in a modern dark room, but it may be necessary to modify it. The projection image is superior. The entire unit is 44 cm long, 12.5 cm wide, 31 cm high and weighs 8.5 kg. This sale includes the following manual: Illustrated Parts List Replacement Projector Type SP3.