Kahler Geodetic Transit

This transit was made in 1877 for the new John C. Green Astronomical Observatory at Princeton University, and resembles the instruments that Stackpole & Brother had made for the 1874 transit of Venus. It has a "broken" telescope that is viewed through one end of the horizontal axis, a micrometer eyepiece, a cast-iron base, and a mechanism that is used to lift and reverse the telescope. The vertical circle is silvered, graduated to 10 minutes, and read by opposite verniers to 10 seconds.
The signature reads "No 145 EDWD KAHLER WASHINGTON, D.C." Edward Kahler (1832–1890) was born in Germany, and is listed in Washington, D.C., directories from 1869. Charles A. Young, the newly appointed astronomer at Princeton, carried on a lengthy correspondence with Kahler, repeatedly modifying the design even as the instrument was being built for the university's new observatory.
Ref: Charles A. Young Papers, Princeton University Archives.
Currently not on view
Object Name
geodetic transit
Kahler, Edward
telescope: 30 in; 76.2 cm
aperture: 2 3/4 in; 6.985 cm
vertical circle: 10 in; 25.4 cm
place made
United States: District of Columbia, Washington
ID Number
catalog number
accession number
See more items in
Medicine and Science: Physical Sciences
Measuring & Mapping
Surveying and Geodesy
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Princeton University
Additional Media

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