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Physical Sciences Collection - Surveying and Geodesy

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Geodetic Transit - click to enlarge

Geodetic Transit - click to enlarge

Geodetic Transit - click to enlarge

Geodetic Transit - click to enlarge

Click photos to enlarge.

Geodetic Transit

Catalogue number:
PH*307210

Inscriptions:
"Troughton & Simms, London, 1849" and "U. S. C. S. No. 6"

Dimensions:
telescope 3 inches aperture, 46 inches long; striding level 26 inches

Discussion:
Troughton & Simms made this instrument for the United States 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.

Further Information:

Geodetic Transit
Troughton & Simms

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