How to set up a theodolite

During the course of training for the practice of land surveying, the surveyor candidate or student will be trained to set up a theodolite. A theodolite can be optical or electronic. In both cases, the process is the same. It is a precise and time-consuming process, learnt in part by experience and in part by theory.

The end result, if properly accomplished is worth the effort.

Set the tripod over the survey point with the head level and legs making about a 70-degree angle with the ground. Mount the theodolite on the tripod.

Secure the front tripod leg and move the two other legs to centre the theodolite by using the plumb bob. Secure the back two legs.

Adjust the length of one leg of the tripod at a time, while keeping the other two still. Use the plumb bob to level the circular bubble without disturbing the centring.

Rotate the theodolite on the tripod head until its plate bubble is parallel to any two footscrews. Adjust those two footscrews to centre the bubble.

Rotate the theodolite body 90 degrees to the left. Center the bubble with the third footscrew. Repeat until the bubble is centred for all four positions.

Loosen the tripod screw. Rotate the theodolite body around until centred over the survey point, then tighten the screw. Repeat the levelling process until the theodolite is level and centred.