- Hoping to improve our understanding of 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 an identical set of apparatus made by Alvan Clark & Sons. For photographing the sun, each party had a horizontal telescope—known as a photoheliograph—with a lens of 5-inches aperture and nearly 40 feet focal length. This is one of those lenses. The “Kerguelen” inscription on the cell indicates that this lens was used at the observing station on a Kerguelan island in the southern Indian Ocean.
- Ref: Simon Newcomb, ed., Observations of the Transit of Venus, December 8-9, 1874 (Washington, D.C., 1880), pp. 25-26.
- Currently not on view
- Object Name
- date made
- Alvan Clark & Sons
- place made
- United States: Massachusetts, Cambridge
- overall: 1 5/8 in x 6 in; 4.1275 cm x 15.24 cm
- ID Number
- catalog number
- accession number
- Credit Line
- U.S. Naval Observatory
- Science & Scientific Instruments
- See more items in
- Medicine and Science: Physical Sciences
- Data Source
- National Museum of American History
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