Octant

A sailor lined up the sun and the horizon with mirrors, and the angle on the arc helped fix the ship's position.

Date: mid 19th century
Maker: E. & G. W. Blunt
Place: United States: New York, New York City
Dimensions: radius: 11 in; 27.94 cm; overall: 3 in x 11 1/8 in x 12 1/4 in; 7.62 cm x 28.2575 cm x 31.115 cm
Museum: National Museum of American History

Octant with an ebony frame, reinforced brass index arm, and telescopic sight. The ivory scale is graduated every 20 minutes from -2° to +111° and read by vernier and tangent screw to single minutes of arc. The "E. & G. W. BLUNT, New York" inscription may indicate that it was made after 1857 when the Blunts began offering nautical instruments "of American manufacture," and before 1866 when the firm became Blunt & Nichols.

The inscription on the brass nameplate reads: "George Davidson. Philadelphia, Pa." George Davidson (1825-1911) was a surveyor, geodesist and astronomer affiliated with the U.S. Coast Survey.

Ref: Deborah J. Warner, "American Octants and Sextants: The Early Years," Rittenhouse 3 (1989): 86-112, on 91-92.

"George Davidson," American National Biography, vol. 6, pp. 143-144.

The museum's own record (Smithsonian, National Museum of American History)

Octant

Also by E. & G. W. Blunt see all

Also made in New York City see all

Also answering “Where am I?” see all