This is a .5 power lens used in the Bausch & Lomb Zoom 240 Stereoscopic Viewer on the Cutler Hammer AIL 1540 light table. This light table was used by the U.S. intelligence community to analyze film from photoreconnaissance satellites and aircraft beginning in 1971. In contrast to earlier light tables, the AIL 1540 had motorized film drives, microscope mounts, and elevation control. It could handle 70 mm and 5 inch, 6.6 inch and 9 inch wide film, and permitted the viewing of two stereo rolls simultaneously. Despite the introduction of computerized systems in 1981 to process imagery returned digitally from photoreconnaissance satellites and aircraft, light tables such as the AIL 1540 are still used today with older imagery that has never been digitized.
The National Geospatial-Intelligence Agency transferred this artifact to the Museum in 2004.
Transferred from the National-Geospatial Intelligence Agency