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Astronomical Quadrant

Astronomical Quadrant

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This portable astronomical quadrant, which resembles English instruments of the late eighteenth century, has a 12-inch radius, stands 17 inches high, and could be used for measuring star altitudes. It belonged to Andrew Ellicott (1754-1820), a surveyor/geodesist who ran the boundaries of several American states, and who probably made it for his own use. The lenses are original. Andrew Ellicott Douglass added the tangent screw in 1885.
Currently not on view
Object Name
Astronomical Quadrant
associated dates
1931 10 28 / 1931 10 28
1899 01 26 / 1899 01 26
1796 00 00 / 1796 00 00, 1890 00 00 / 1890 00 00
Ellicott, Andrew
associated place
United States: Arizona, Tucson
United States: Arizona, Flagstaff
Physical Description
metal, brass (overall material)
glass (overall material)
original lenses. (container material)
average spatial: 45.1 cm x 30.5 cm x 24.8 cm; 17 3/4 in x 12 in x 9 3/4 in
overall: 17 5/8 in x 13 1/4 in x 13 3/8 in; 44.7675 cm x 33.655 cm x 33.9725 cm
ID Number
accession number
catalog number
See more items in
Medicine and Science: Physical Sciences
Data Source
National Museum of American History
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