The octant has an ebony frame and limb with a brass index arm, fittings, and a brass stop for the index arm. It also has an inlaid ivory plate on the back of the frame. There is no tangent screw and the clamping screw is on the back of the index arm. The octant has three socket shades, two red and one green. Index-glass adjustment is made by a screw and on both horizon glasses by screws, levers, wing nuts and milled clamping screws. The sight vane has two pinholes and a swivelling shutter, whereas the back sight vane has one pinhole. A brass-capped screwdriver is fitted in the crossbar. The octant is contained in a stepped oak box, with two trade labels for C. W. Dixey, 3 New Bond Street, London (1839-62).

The instrument has an inlaid ivory scale from -2°, which is off the arc, to 99° by 20 arcminutes, measuring to 91°. The octant has an ivory vernier measuring to 1 arcminute, with zero at the right.