Image Archive

Detailed Record

Title: Device for solving navigational triangle

Accession Number: 1957.617
Type: Japanese computer
Place: JAPAN
Description: Protractor of metal, painted green. Consists of 2 complete circles, the one at the base capable of being rotated, and marked on half of it in 360 degrees. Upright circle at back marked to 90 degrees for latitude, with brass knob for control of each. 2 Sights, and 3 half circles, center one with 2 handles for raising or lowering entire arc; 2 other knobs on instrument and some print in Japanese. This instrument, given 3 factors such as dead reckoning of latitude, declination of the sun and altitude, computes the 4th, longitude.

Mystic Seaport Image ID m154536    Information regarding reproductions