Model Number: 1403

Manufacturer: Jesse Ramsden, London, England

Manufactured: ca 1795

Description:
Brass sextant with silver beveled scale, divided from -5 to 155 in 20 arc minute increments. Features vernier reading to 30 arc seconds, clamping screw, fine adjustment screw, swing-away scale magnifier, and adjustable horizon glass. Object Size: 4-1/2" (radius); 5-1/4" (length) x 4" (height) x 5-3/4" (width).

Item History:
Developed after 1757, sextants were designed to measure angles up to 120 degrees for celestial navigation, gradually replacing octants. Used to determine latitude by measuring celestial body altitude above the horizon.