Smithsonian - National Museum of American History, Behring Center

 
Physical Sciences Collection - Surveying and Geodesy

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Alidade
Altitude and Azimuth Instrument
Chain, Tape and Base Bar
Compass, Pocket
Compass, Railroad
Compass, Solar
Compass, Surveyor's
Cross, Surveyor's
Electromagnetic Distance Measurement (EDM)
Gradienter
Graphometer
Heliotrope
Holland Circle
Level
Range Finder
Repeating Circle
Theodolite
Transit
Transit and Equal Altitude
Transit, Geodetic
Universal Instrument
Vertical Circle
Waywiser
Zenith Telescope
Miscellaneous

 

Geodetic Transit

A geodetic transit observes the transit of a celestial body over the meridian. In the early 19th century, geodetic transits were used primarily to determine local time. In the 1860s the United States Coast Survey began using these instruments, in connection with an electric telegraph, to determine longitudes. In the late 1870s, the Survey began using transits equipped with striding levels and micrometer eyepieces to determine latitude, in the same way that had been done with a zenith telescope.

Ref:

C. A. Schott, "Determination of Time by Means of the Transit Instrument," United States Coast Survey Annual Report (1866), Appendix No. 9.

George Davidson, "Description of the Davidson Meridian Instrument," United States Coast and Geodetic Survey Annual Report (1879), Appendix No. 7.

Collection:

Bamberg
Fauth
Fauth (prismatic)
Jones, Thos.
Kahler
Patten & Son
Stackpole & Brother #1504
Troughton & Simms
Troughton & Simms (dated 1849)
USC&GS No. 18