Smithsonian - National Museum of American History, Behring Center

Physical Sciences Collection - Surveying and Geodesy

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Theodolite - click to enlarge

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Catalogue number:

"WILD HEERBRUGG SWITZERLAND T-3 91599" "1969 US" and "CONTR DSA-700-69-C-G570 FSN 6675-411-5446

height 14.5 inches; horizontal circle 5.5 inches diameter; vertical circle 3.73 inches diameter; telescope 2.37 inches aperture, 10.25 inches long


Heinrich Wild's Precision Theodolite, introduced in 1925 and later known as the T3, is a geodetic version of the T2. The horizontal and vertical circles are glass, and read directly to .2 seconds. The telescope has a range of 20-60 miles. With some modifications, the T3 remained in production for about 50 years. The United States Coast and Geodetic Survey described the T3 as a "satisfactory first-order instrument" suitable for the most exacting survey work. The United States Army published a detailed account of the maintenance and use of the T3 in 1963. The Geodetic Survey Squadron, a branch of the United States Air Force that became part of the United States Defense Mapping Agency when that organization was formed in 1972, used T3s to provide orientation at launch sites for missiles and satellites. The National Imagery and Mapping Agency, successor to DMA, transferred this T3 to the Smithsonian in 2000. It was apparently purchased in 1969, and has its original air tight and water tight steel case, and its original wooden shipping case. A decal on the shipping case reads "DEFENSE MAPPING AGENCY, GEODETIC SURVEY SQUADRON."

Ref: Wild, The New Precision-Theodolite Wild T3 (Heerbrugg, 1939).

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