This is a typical example of a portable reversible transit instrument. It comprises of a telescope with pivots, a stand and a level which sits on the two pivots where the telescope and stand meet.

A transit instrument is a telescope pivoted on a stand so that it can only move in one plane. Normally this would be aligned north-south so that as the Earth turns, every star visible from the latitude of the telescope can be seen to rise and fall over the course of a year. These types of telescopes can be used to create star charts, since every star can be viewed and so plotted. The time at which each star crosses the north-south line, or meridian gives one co-ordinate, the angle the telescope must point at to see it (its angular height) gives the other. It can also be used to find the time by the stars.

Telescope: The telescope has an aperture of 40mm (1.6inches). It has a focal length of 419mm (16.5inches). The distance between the two pivots is 269mm (10.6inches).

Stand: The brass stand is 305mm (12inches) tall.

Accessories and box: The fitted wooden box is designed to hold the stand, telescope, spirit level, right angle eyepiece, object glass and unident turning rod.