edm

Study and Use of conventional Surveying Instruments and EDM Devices

ByEngr.Sidra Shahid

Transit Theodolite

The Transit Theodolite

• Trivet• Foot Screw• Tribrach• Levelling head

The Transit Theodolite

• Lower Plate• Upper plate• Plate Bubble

The Transit Theodolite

• Telescope • Vertical Circle• Index bar or T frame• Altitude Bubble • Compass

Centering•The setting of theodolite exactly over

a station mark by means of plumb bob

• The plumb bob is suspended from hook fixed below the vertical axis

Face leftThe vertical circle of the

theodolite is on the left of the observer at the time of taking

readings

Face RightThe vertical circle of the

theodolite is on the right of the observer when the

readings is taken

Telescope NormalThe face left position is known as ‘telescope normal’ or ‘telescope

direct’.It is also referred as ‘Bubble up’.

Telescope InvertedThe face right position is known as ‘telescope inverted’ or ‘telescope

reversed’.It is also referred as ‘Bubble down’.

Changing faceThe operation of bring the

vertical circle from one side of the observer to the other.

Swinging the telescope

This indicates turning of the telescope in a horizontal plane .it is called “right swing” when the telescope is turned clockwise and “left swing” when the telescope is turned anticlockwise.

Line of Collimation • It is an imaginary line passing

through the intersection of the cross hairs at the diaphragm and the

optical centre of the object glass and its continuation

Axis of the telescope

• This axis is an imaginary line passing through optical centre

of the object glass and the optical centre of the eye piece

Axis of the bubble tube

•This axis is an imaginary line tangential to the longitudinal curve of the bubble tube at

its middle point.

Vertical axisThis axis of rotation of the telescope in the horizontal plane

Horizontal axisThis axis of rotation of the telescope in vertical plan. It is also known as the turnnion axis.

Temporary adjustment

The setting of the theodolite over a station at a time of taking any observation.• It is necessary for every set up of

the instrument.

Any Question ???

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