Octant by Smith of Aberdeen, Mid 19th Century

The maker's nameplate is inscribed SMITH * ABERDEEN, however we have not uncovered any historical records of Aberdeen instrument makers, so the maker of this octant (Smith) is a bit of a mystery. But given it's construction, we can narrow down the date of manufacture to the mid 19th Century.

The octant has an ebony wood frame, a reinforced brass index arm with index mirror and vernier adjustment. The main ivory scale has a measurement range of -2 to 100 degrees. The scale has fine graduations marked every of 20 minutes of arc, minor graduations every 1 degree and major, marked graduations every 5 degrees (starting at zero). The ivory vernier scale has fine graduations of 1 minute of arc and minor marked graduations every 5 minutes of arc.

There are three colour tinted glass shades for the sun sight and three shades for the horizon sight.

The ivory pencil holder is still intact, as is the ivory plate on the rear of the octant frame where the navigator would record the reading for the sighting.

The radius of the octant, which is the length of index arm from the mirror pivot point to the bottom edge of the vernier scale, is 25.4 cm (10").

The octant sits in a keystone mahogany box on three brass supports. Inside the lid is the label of the merchant "Robert Park, Optician & Nautical Instrument maker, Greenock"