The telescope is an integral part of odolite. It is mounted on a spindle known as a horizontal axis or trunnion axis.

The operation of setting up includes centering of instrument over station mark by a plumb Bob or by optical plummet and appropriate levelling with help of tripod legs.

The index frame is a T shaped frame consisting of a vertical leg known as clipping arm. It is also called a Vernier frame.

When instrument stations are at different instrument levels, re would be two heights, off which, h₁ can be calculated by
h₁ = (s + b*tan?₂)*tan?₁ / (tan?₁ ? tan?₂). By substituting required values we get, h₁ = (1.295 + 1.2 * tan4⁰44?) / (tan9⁰24? ? tan4⁰44?) = 2.79 m.

The adjustments applied to angles are independent of size of angle because y depend on direction in which y are present.

From figure, h = D tan ?₁ and h = (b +D) tan ?₂
By equating we get,
D tan ?₁ = (b + D) tan ?₂
D = (b tan ?₂) / (tan ?₂ ? tan ?₁).

In first method of taking a single set, after keeping telescope normal throughout we measure angle clockwise by 6 repetitions. We obtain first value of angle by dividing final reading by 6.

If line of sight is inclined, vertical distance calculated will include values of sin which is derived from horizontal distance formula i.e., V = Ks \(\frac{sin2?}{2}\) + C sin ?.

Any angle in Whole Circle Bearing system can be transformed into reduced bearing system by using a relation, it can be given as
R.B = 180⁰ ? W.C.B which means R.B = 180⁰ ? 162⁰24? = 17⁰26? = S17⁰26?E.
In R.B system, direction of angle is also mentioned along with value.

The personal errors may be due to errors in manipulation, errors in sighting and reading. Manipulating wrong tangent screw comes under errors in manipulation.