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Bubble Sextant

Catalogue number:
NASM 1957-296

Inscriptions:
"BRANDIS & SONS, INC. / BROOKLYN, N.Y. / 206B-40" and AERONAUTICAL OCTANT / MARK I MODEL 3 / U.S.N. SERIAL 20-29" and "WILLSON TELESCOPE / PATENTS PENDING / 206B-40"

Dimensions:
radius 5.25 inches

Discussion:
This is a small left-handed octant with a Willson bubble telescope, a Fischer rapid release lever, a drum micrometer, an electric light over the divided scale, and a battery in the handle. The Navy Bureau of Aeronautics designated it the Mark I, Model 3. The National Bureau of Standards transferred this instrument to the Smithsonian in 1957. It was the 40^th example of the Model 206B and the 20^th example made for the Navy in 1929.

Ref: R. W. Willson, "Instrument Including Means for Determining the Horizontal Direction," U.S. Patent #1,705,146

Pioneer Instrument Co., Pioneer Instruments and Equipment (Brooklyn, ca. 1930).

Further Information:

Brandis
Aircraft Sextant