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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Theodolite

Catalogue number:
1997.0290.04

Inscriptions:
"Kern AARAU SUISSE SWITZERLAND No 37845 DKM2"

Dimensions:
height 8.25 inches

Discussion:
Heinrich Wild designed this DKM2 (a double circle theodolite with an optical micrometer) for Kern in the 1930s. Like the T2 manufactured by Wild in Heerbrugg, the DKM2 is a light weight instrument with a steel frame. The horizontal and vertical circles are glass, and read directly to single seconds. The telescope is equipped with stadia wires, and so can be used for tachymetry. An auxiliary eyepiece lying alongside the telescope allows the user to read either circle without moving away from the station. Here, however, the 2 scales are read through the optical micrometer with reference to a centrally located index, giving the arithmetic mean of two diametrically opposed points on the circle. In 1955, an instrument of this sort, with tripod, cost $1,221. This instrument was purchased in 1963, and given to the Smithsonian in 1997.

Ref: Kern & Co., Ltd, Double Circle Theodolites (about 1959).

Further Information:

Kern
Wild
Theodolite

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