Zenith Telescope
date: label: date made
content: 1840s
name: label: Associated Name
content: International Geodetic Association
label: Associated Name
content: U.S. Coast and Geodetic Survey
label: maker
content: Troughton and Simms
notes: label: Description
content: Marked "Troughton & Simms, London" and "U. S. C. S. Z. T. No 1," this is the first of four identical zenith telescopes that Troughton & Simms made for the U. S. Coast Survey. Designed for the determination of latitude by the Talcott method, the telescope arrived in the United States in 1847. In 1891 it was sent to San Francisco for use in the variation of latitude (polar motion) program organized by the International Geodetic Association. C. A Schott, the assistant in charge of the computing division of the Survey, noted at that time that this instrument was far from ideal, its "principal defect" being "a lack of stability; hence demanding great caution in handling it."
label: Description
content: This zenith telescope was transferred to the Smithsonian in 1911. Correspondence in the accession file indicates that it was modified by William Wurdemann in 1867, and fitted with two levels in the early 1890s.
label: Description
content: Ref: C. A. Schott, "The Variation of Latitude at San Francisco, Cal., as Determined from Observations made by George Davidson, Assistant Coast and Geodetic Survey, Between May, 1891, and August, 1892," <i>United States Coast and Geodetic Survey Report for 1893</i>, Appendix No. 11, p. 447.
label: Location
content: Currently not on view
place: label: place made
content: United Kingdom: England, London
setName: label: See more items in
content: Medicine and Science: Physical Sciences
label: See more items in
content: Surveying and Geodesy
label: See more items in
content: Measuring & Mapping
publisher: label: Related Publication
content: United States Coast and Geodetic Survey Report for 1893
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: PH.270200
label: catalog number
content: 270200
label: accession number
content: 53077
objectType: label: Object Name
content: zenith telescope
physicalDescription: label: Measurements
content: overall: 48 1/2 in x 14 1/2 in x 15 1/2 in; 123.19 cm x 36.83 cm x 39.37 cm