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The term transit theodolite, or transit for short, refers to a type of theodolite where the telescope is short enough to rotate in a full circle on its horizontal axis as well as around its vertical axis. It features a vertical circle which is graduated through the full 360 degrees and a telescope that could "flip over" ("transit the scope").
The initial setting operation includes fixing the theodolite on a tripod, along with approximate levelling and centering over the station mark.For setting up the instrument, the tripod is placed over the station with its legs widely spread so that the centre of the tripod head lies above the station point and its head approximately level (by eye estimation).
The permanent adjustments of theodolites are made to establish fixed relationship between the instrument's fundamental lines. The fundamental lines or axis of a transit theodolite include the following:- Vertical axis; Axis of plate levels; Axis of telescope; Line of collimation; Horizontal axis; Axis of altitude bubble and the vernier should ...
The alidade is the part of a theodolite that rotates around the vertical axis, and that bears the horizontal axis around which the telescope (or visor, in early telescope-less instruments) turns up or down. In a sextant or octant the alidade is the turnable arm carrying a mirror and an index to a graduated circle in a vertical plane. Today it ...
Diagram of measurements: D is the slant distance; S is the horizontal distance; Δh is the vertical distance. Tacheometry ( / ˌ t æ k i ˈ ɒ m ɪ t r i / ; from Greek for "quick measure") is a system of rapid surveying , by which the horizontal and vertical positions of points on the Earth's surface relative to one another are determined ...
Ramsden made at least one other 3-foot (0.91 m) theodolite of which parts were discovered in Switzerland. [2] After his death his firm was inherited by Mathew Berge who is known to have constructed two more large instruments to Ramsden's design. [ 2 ]
A total station or total station theodolite is an electronic/optical instrument used for surveying and building construction. It is an electronic transit theodolite integrated with electronic distance measurement (EDM) to measure both vertical and horizontal angles and the slope distance from the instrument to a particular point, and an on ...
Leonard Digges (c.1515 – c.1559) was a well-known English mathematician and surveyor, credited with the invention of the theodolite, and a great populariser of science through his writings in English on surveying, cartography, and military engineering. His birth date is variously suggested as c.1515 [1] or c.1520 (but certainly by 1530). [2]