Essential parts of a theodolite

1. Tripod

It should be of a rigid type capable of fixing the position of the instrument with a small lateral movement on its top when required.

2. Foot screws

These are provided for leveling the instruments.

3. Plate level

Provided for checking the level of the instrument.

4. Horizontal clamp

Provided to clamp the movement in horizontal plane.

5. Vertical clamp

For clamping movement in vertical plane.

6. Slow motion screws

These screws are used to move Theodolite either vertically or horizontally in small fractions.

7. Telescope

In a telescope vertical hair is used for horizontal angle measurement while horizontal hair is used for vertical angle measurement. Focusing arrangement for the object glass is usually provided in the body of the telescope. Collimator is provided to bring the object in the field of view.

8. Vertical axis

It is the axis around which the telescope rotates in horizontal plane.

9. Horizontal axis

It is the axis around which telescope rotates in vertical plane.

10. Optical plummet

It is provided for centering the instrument over a ground station.

11. Angle reading arrangement

In screen display you can note angle measurements taken with Theodolite.