What is Theodolite and its Types?


A theodolite refers to a precision optical instrument for measuring angles. These angles are between the designated visual points in the horizontal and vertical planes. Students can explore more about theodolite and it types here.

What is Theodolite?

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.


Types of  Theodolite

Modern theodolites involve a movable telescope which is mounted within two perpendicular axes. Moreover, these two axes are the horizontal axis and the vertical axis.

When the telescope focuses on a target object, the measurement of the angle of these axes takes place with high precision. Theodolites generally include three types.

Repeating Theodolite

Repeating theodolites refer to those theodolites which measure angles on a graduated scale. The average of the angle measure is then derived. This takes place by dividing the total of these readings by the number of readings which were taken.

The use of repeating theodolites takes place in locations where the base is not steady. Furthermore, their use also occurs in places where space is too limited. This limited space makes the use of other instruments futile.

Repeating theodolites are certainly more accurate than other types of theodolites. This is because a reduction of errors takes place here. This is possible due to comparing the values of multiple readings rather than a single reading.

Direction Theodolites

Direction theodolites refer to those theodolites which determine angles through a circle. Here, a circle is set and the direction of the telescope is at several signals.

An individual can acquire readings from every direction. The determination of the angle measurements is by subtracting the first reading from the second reading.

The common usage of direction theodolites is by surveyors in triangulation. Moreover, triangulation is the process of determining a point by measuring the angles from certain known points on a baseline.

Vernier Transit Theodolite

Vernier transit theodolites are those which carry a telescope which flips over to allow back sighting and angle doubling. Most noteworthy, this result is quite a few errors in reading.

The precision of these theodolites is less in comparison to other types. This is because they lack important features like magnification or measurements in micrometres.

Significant usage of vernier transits is on construction sites. This is because they are relatively lightweight which means they can be moved around easily.

Some Vernier transit theodolites measure both vertical and horizontal angles. However, there are some vernier transit theodolites which measure only horizontally.

Solved Question For You

Q1 Which of the following is not a type of Theodolite?

A. Magnetic theodolite
B. Vernier Transit theodolite
C. Direction theodolites
D. Repeating theodolite

A1 The correct answer is option A.

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Hamza Afzal

I was looking for this answer, “As all the other are mild steel means they have high resistance while stainless steel is a hard steel that has low resistance.” stainless steel has low resistance?
Low resistance to what type of load, impact or tensile load. With change in low type, property of steel may very. And, also, Will stainless steel have high yield strength?

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