Roof Prism

Roof Prism

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After the United States declared war on Germany on April 6, 1917, American leaders realized that the best optical instruments came from German shops. Thus, to obtain the spy glasses, binoculars, range finders, and other optical instruments needed by its fighting forces, they commandeered the resources of private optical and instrument shops. And they authorized the establishment of a new optical shop at the Washington Navy Yard. That facility, later termed the Naval Weapons Plant Optical Shop, gave this glass roof prism, for a telescope, to the Smithsonian in 1961.
Currently not on view
Object Name
Prism, Telescope
Physical Description
glass (overall material)
overall: 76 mm x 40 mm x 40 mm; 3 in x 1 9/16 in x 1 9/16 in
overall: 1 9/16 in x 3 in x 1 5/8 in; 3.96875 cm x 7.62 cm x 4.1275 cm
ID Number
catalog number
accession number
See more items in
Medicine and Science: Physical Sciences
Data Source
National Museum of American History
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