Theodolites

A Theodolite is a precision instrument for measuring angles in the horizontal and vertical planes. Theodolites are mainly used for Surveying and setting out applications. A modern Theodolite consists of a movable telescope mounted within two perpendicular axes - the horizontal or trunion axis and the vertical axis. When the telescope is pointed at a target object, the angle of each of these axes can be measured with great precision, typically to seconds of arc.