Objective Lens

Objective Lens

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Usage conditions apply
In an effort to get a better fix on the distance between the Earth and the Sun, the United States sponsored eight parties to observe the 1874 transit of Venus across the face of the sun, and equipped each with apparatus made by Alvan Clark & Sons. This 5-inch aperture lens in a brass cell was the objective for one of the eight equatorial refractors. The “VIII Nagasaki 1 / Fort Selden N.M.” inscription scratched on the cell indicates that this was used at Nagasaki in 1874, and Cerro Roblero (a site near Fort Selden, an Army post in what is now New Mexico) during the transit of Venus of 1882.
Ref: Simon Newcomb, ed., Observations of the Transit of Venus, December 8-9, 1874 (Washington, D.C., 1880), p. 16.
Currently not on view
Object Name
telescope objective lens
date made
Alvan Clark & Sons
place made
United States: Massachusetts, Cambridgeport
overall: 1 1/2 in x 5 3/4 in; 3.81 cm x 14.605 cm
overall: 1 5/8 in x 6 in; 4.1275 cm x 15.24 cm
ID Number
catalog number
nonaccession number
Science & Scientific Instruments
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Medicine and Science: Physical Sciences
Data Source
National Museum of American History
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