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 inlaid plates on the crossbar and the back of the frame, both of which are missing. The tangent screw and clamping screw are positioned 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 milled clamping screw. The sight vane has two pinholes and a swivelling shutter. An ivory cap for a pencil is fitted in the crossbar. The left strut is cracked. The octant has no box.

The instrument has an inlaid ivory scale from -2° to 100° by 20 arcminutes, measuring to 96°. The octant has an ivory vernier measuring to 1 arcminute, with zero at the right.