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Octant

Catalogue number:
AF*59400-N

Inscriptions:
"SPENCER & C^O LONDON"

Dimensions:
radius 9.5 inches

Discussion:
This octant was made around 1817. It has an ebony frame, reinforced brass index arm, and ivory name plate. The ivory scale is graduated every 20 minutes from about -3^o to +100^o and read by vernier with tangent screw to single minutes of arc. There is a peep sight, four shades for the index mirror, and three shades for the horizon glass. The Smithsonian purchased it in 1965.

Further Information:

Spencer & Co.
Octant