Theodolite built by the Officine Galileo, mounted on a tripod with leveling screws and fitted with two telescopes. The upper telescope, with a bubble level, is adjustable vertically and horizontally. There are two scales for measuring its inclination. The second telescope, which lacks an objective lens, was used to aim at a fixed reference point, ensuring that the instrument was always correctly oriented during the measurement operations. There were four small micrometer microscopes (of which two are now missing) for an accurate reading of the scales. There is an auxiliary platform for carrying optical components such as prisms and mirrors.