Photograph from the Papers of Harold E. Edgerton (MC 25)
The U.S. Army Air Force asked MIT's Harold Edgerton in 1939 to design a flash lamp strong enough to enable aerial photography by night of enemy activities on the ground. Reliable nighttime surveillance was important because military commanders often disguise their intentions and the strength of their preparedness by moving troops and materiel under mask of darkness. Edgerton, who had earlier perfected the stroboscope and was adept at using his high-speed Strobotac flash units to freeze motion and analyze scientific and industrial problems, accepted the military's challenge as the clouds of impending war gathered in Europe. What the Air Force required was a flash unit thousands of times more powerful than the Strobotac, which had been designed for indoor use at close range. Between 1939 and 1944 Edgerton supervised the development, testing, and deployment of six models of nighttime aerial flash equipment suitable for various planes and situations. His work bolstered the Allied cause with vital intelligence about enemy strengths and weaknesses during the Italian campaign, in the Far East, and immediately prior to the Normandy invasion on D-Day, June 6, 1944.
The nighttime aerial photo seen above (now declassified) shows the destruction of a bridge and disruption of rail connections somewhere near the German Gustav Line between Naples and Rome during the five-month Battle of Monte Casino in the winter of 1944. The Germans' dogged defense of the Gustav Line slowed the Allied advance up the leg of Italy and led to cancellation of plans to launch an amphibious invasion in the south of France. Note the clarity of detail, the frozen motion of the plane's rapidly spinning propeller, and the numerous craters from bombs that fell short of or sailed beyond the target. The image fades to obscurity at the corners and edges, defining the limits of the flash's area of effective illumination.
The second picture illustrates the process of inspecting, sorting, and classification of records produced during the war. In this case the records are the nighttime aerial surveillance photographs produced using Edgerton's equipment and techniques. Such records once served an immediate and urgent purpose in support of Allied victory. They have now become an interesting and valuable resource for historical analysis and reflection.
Edgerton's World War II work is well documented by materials, including these photographs, preserved in the Harold E. Edgerton Papers (MC 25), in the MIT Institute Archives and Special Collections. Reports, photographs, blueprints, correspondence, and reminiscences on audiocassette are available in the Archives, 14N-118.
Object of the Month: May 2001
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