Theodolite is a precision instrument whose main purpose is for measuring angles in the horizontal and vertical planes. The main usage of theodolites is for surveying applications. Furthermore, they are also used for specialized purposes in fields like metrology and rocket launch technology. theodolite, basic surveying instrument of unknown origin but going back to the 16th-century English mathematician Leonard Diggers; it is used to measure horizontal and vertical angles. In its modern form it consists of a telescope mounted to swivel both horizontally and vertically. Leveling is accomplished with the aid of a spirit level; crosshairs in the telescope permit accurate alignment with the object sighted. After the telescope is adjusted precisely, the two accompanying scales, vertical and horizontal, are read.
What is the principle of theodolite?
It consists of a moveable telescope mounted so it can rotate around horizontal and vertical axes and provide angular readouts. These indicate the orientation of the telescope, and are used to relate the first point sighted through the telescope to subsequent sightings of other points from the same theodolite position.
Following are the parts of a theodolite:
Telescope
Vertical circle
Index frame
The standards
The upper plate
The lower plate
The leveling head
The shifting head
Plate level
Tripod
Plumb bob
Magnetic compass
Venier Theodolite---The vernier is an auxiliary graduation, placed alongside the main one with the purpose of determining fractions of the graduation unit. The vernier is typically used with theodolites of medium or low accuracy, as well as for simple angle measuring devices.
What is horizontal and vertical angle?
An angle is defined as the difference in direction between two convergent lines. A horizontal angle is formed by the directions to two objects in a horizontal plane. A vertical angle is formed by two intersecting lines in a vertical plane, one of these lines horizontal.