Troughton & Simms Geodetic Transit

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This instrument marked "Troughton & Simms, London, 1849" and "U. S. C. S. No. 6" was made for the U. S. Coast Survey in 1849. It has a double-cone horizontal axis, two lamps for illuminating this axis, a large striding level, two small vertical circles attached to the telescope tube, and a solid iron base. By 1880, The Coast Survey had added the eccentric cam apparatus to the base to facilitate the reversal of the telescope.
Ref: "Determination of Time by Means of the Transit Instrument," United States Coast and Geodetic Survey Report (1880): 205-227 and pl. 62.
Currently not on view
Troughton and Simms
place made
United Kingdom: England, London
telescope: 46 in; 116.84 cm
aperture: 3 in; 7.62 cm
striding level: 26 in; 66.04 cm
ID Number
accession number
catalog number
Credit Line
U. S. Coast and Geodetic Survey
See more items in
Medicine and Science: Physical Sciences
Measuring & Mapping
Surveying and Geodesy
Data Source
National Museum of American History


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