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Bubble Sextant

Catalogue number:
NASM 1962-72

Inscriptions:
"KEUFFEL & ESSER CO. / NEW YORK / 57324 / PAT. PENDING" and "BUBBLE OCTANT MARK II, MOD. 2 / BUREAU OF AERONAUTICS. U.S. NAVY / SERIAL NUMBER 3-29 / MADE BY / KEUFFEL & ESSER CO. / N.Y." and "EXPERIMENTAL HANDLE BRACKET MARK II MOD 2"

Discussion:
The Mark II, Model 2 was designed by Noel Davis, modified by Keuffel & Esser, and produced for the U.S. Navy. This example was the 3^rd one made in 1929. The Naval Observatory transferred it to the Smithsonian in 1957.

Ref: T. C. Lonnquest, "Operation and Adjustment of the Mark II Model 2 Octant," Bureau of Aeronautics, Navy Department, Technical Note No. 207 (Nov. 22, 1929).

Lawrence Radford and Noel Davis, "Sextant," U.S. patent #1,743,979.

Further Information:

Keuffel & Esser
Aircraft Sextant