Geodetic Transit

Geodetic Transit

<< >>
Usage conditions apply
Downloads
Description
This transit marked "USC&GS No. 18" was designed by E. G. Fischer, chief mechanician of the U. S. Coast and Geodetic Survey. It is one of two identical instruments that were built in the Survey's instrument shop in 1888–1889. They were said to be "the most complete and best constructed transits the Survey has ever had for longitude." They had about the same optical power as the transits that Troughton & Simms had made in the 1840s, but weighed substantially less. When packed in two boxes for transportation, each instrument weighed "only" about 350 pounds. John Clacey made the objective lenses, and Edward Kahler made the eyepieces.
G. N. Saegmuller, who offered an apparently identical instrument for $900, termed it a "Coast Survey Transit. No. 30" and noted that the Survey used instruments of this sort "for time observations only."
Ref: Edwin Smith, "A Description of Two New Portable Transit Instruments for Longitude Work," Report of the Superintendent of the U.S. Coast and Geodetic Survey for 1889 (Washington, D.C., 1890), Appendix No. 9.
G. N. Saegmuller, Descriptive Price–List of First–Class Engineering & Astronomical Instruments (Washington, D.C., 1903), p. 75.
Location
Currently not on view
Object Name
geodetic transit
place made
United States: District of Columbia
Measurements
aperture: 3 1/2 in; 8.89 cm
telescope: 39 1/2 in; 100.33 cm
ID Number
PH.316661.01
accession number
226636
catalog number
316661
Credit Line
U.S. Coast & Geodetic Survey
See more items in
Medicine and Science: Physical Sciences
Measuring & Mapping
Surveying and Geodesy
Data Source
National Museum of American History
Nominate this object for photography.   

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.

Comments

Add a comment about this object