A mid 19th century navigators Octant made by G. Rahtjen, Bremen. with applied makers plate.
The Octant’s double ‘T’ shaped frame is constructed from ebony with brass fittings and ivory scales. The arc scale is crisp and clearly engraved, reading from -4 degrees to 108 degrees and further divided into 20 minutes of arc. This Octant can measure angles of up to 87 degrees.
This Octant comes with two telescopes, press on telescope sun filter and mirror adjusting tool. It is also fitted with a hardwood handle and has both index mirror sun shades and horizon mirror sun shades.
This Octant has a braced brass index arm, which is fitted with an ivory Vernier scale engraved from 0 to 20 and reading 1 minute of arc. There is a clamping screw to the reverse side with a fine adjustment tangent screw off to the side.
This Octant has a radius of 9.5 inches / 24cm
SORRY THIS ANTIQUE OCTANT HAS BEEN SOLD.
The Octant preceded the design and development of the Sextant. The Octant was invented by John Hadley and Thomas Godfrey simultaneously in 1731.
The Octant gets its name from the Latin word Octans because it is an eighth of a circle (45 degrees) and can measures angles of up to 90 degrees.
By 1780 the octant had almost completely replaced all previous navigational instruments and was half the size of a Davis Quadrant.
In the early days the instrument frames were made from wood, usually Ebony with Ivory scales, however in the later years of Octant production the frames were made from brass and the scales were either Ivory or silver.
Clipper Maritime Antiques specialises in antique navigation instruments.
We offer a wide selection of top quality antique Sextant’s, Quintant’s and Octant’s, prices range from £300 to over £1000.
Price on request: Please Email us your enquiry or if you would like any help or advice about choosing an antique celestial navigation instrument.
Front side of the antique octant with telescopes, eye piece filter and mirror adjusting tool.
A close up of the antique octant showing ivory scale and index arm Vernier.
Exterior of the hardwood octant carrying case / storage box.
Reverse side of the antique octant and accessories.
Front side of the antique octant.
Reverse side of the antique octant.
Close up of the ivory makers plaque.
Close up of the octant's Vernier and tangent screw.
Close up of antique Octant showing detail.
Close up of antique Octant showing detail.