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Octant

Catalogue number:
PH*309886

Dimensions:
radius 12 inches

Discussion:
This octant has an ebony frame and flat brass index arm. The ivory scale is graduated every 20 minutes from -2^o to +100^o and read by vernier and tangent screw to single minutes of arc. There is also a back sight and back horizon glass used to measure angles greater than 90^o. This instrument was probably made in England around 1800. The U.S. Navy transferred it to the Smithsonian in 1930.

Further Information:

Octant