Theodolite

THEODOLITE:

A theodolite is versatile instrument basically designed to measure horizontal and vertical angles. It is also used to give horizontal and vertical distances using stadia hairs.


PARTS:

·        TELESCOPE has object piece at one end and eye piece at other end and its purpose to focus the object.  It rotates about horizontal axis in vertical plane. The graduations are up to an accuracy of 20’.

·        INDEX FRAME which is also called t-frame or vernier frame having two arms vertical and horizontal. It is used to lock the telescope at a desired level and its horizontal arm is used for taking measurements of vertical angles.

·        THE STANDARDS are also known as A-frame because of its shape. It supports telescope and allow it to rotate about vertical axis.

·        THE UPPER PLATE is also called vernier plate whose top surface gives support to telescope.

·        THE LOWER PLATE has a scale graduated from 0 to 360 that is why it is called scale plate. It can rotate by our willings.

·        THE LEVELLING HEAD contains two parallel triangular plates known as tribratch,the upper one is used to level the upper plate and telescope and lower one is attached to tripod stand.

·        THE SHIFTING HEAD also contains two parallel plates moving one over other with in small area, lies below the lower plate. It is used to center the whole instrument over the station.

·        PLATE LEVEL helps the telescope to settle in exact vertical position.

The purpose of telescope is to see the target.                                     

                          A small bubble is used for leveling of the instrument.         

Market Value: Price per piece of theodolite in US $ 600 to 700 in PKR 83475.