The octant consists of a polished brass plate with a detached boxwood handle. The pointer on the front of the instrument is geared to give 1:4 magnification on the circular scale on the back that is moved by hand. The octant has no shades. The index glass is missing and has been replaced by silver foil.

Index and horizon-glass adjustment (with an indicator showing the value) is made by a screw and a worm screw with a milled knob. The sight vane has two pinholes and a swivelling shutter.

The instrument has a polished brass scale, on the back of the plate, which measures from 0° to 90° by 20 arcminutes. It is indicated by a moving pointer. The octant has a vernier measuring to 1 arcminute, with zero at the centre. The stops to mark the end of the scale are missing. The tip of the pointer is bent, and one screw is missing from the handle. The octant has no box.