The octant has an ebony frame and limb with a brass index arm and fittings. It also has inlaid ivory plates on the crossbar and on the back of the frame. The tangent screw and clamping screw are located on the back of the index arm. The octant has three index shades, two red and one green. Index-glass adjustment is made by a screw and on the horizon glass by a lever, wing nut and a clamping screw. The sight vane has two pinholes and a swivelling shade with the glass missing. An ivory pencil head is fitted in the crossbar. The left strut is cracked and the screw and washer of the sight vane are probably replacements. The octant is contained in an unusual triangular, stained, softwood box with a cracked lid.

The instrument has an inlaid ivory scale from -4° to 100° by 20 arcminutes, measuring to 90°. The octant has a vernier measuring to 1 arcminute, with zero at the right.