A fine mid 19th century navigators Octant made by Andrew Cowie, Grangemouth. With applied makers plate.

The Octant’s ‘T’ shaped frame is constructed from ebony with brass fittings and ivory scales. The arc scale is crisp and clearly engraved, reading from -3 degrees to 110 degrees and further divided into 20 minutes of arc. This Octant can measure angles of up to 93 degrees.

Double-hole sighting pinnula with swing cover. There is a set of three sunshades for the index arm mirror.

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.

The ivory makers plaque is situated on the crossbar of the octant frame and is engraved Andrew Cowie, Grangemouth.

This Octant is complete with its original hardwood keystone shaped oak box. (some repairs to the box are present)

Height of Octant: 11 inches / 28 cm,

Radius of Octant: 9.5 inches / 24 cm.