L5: Theodolites

Question 1

What are theodolites used for?

Answer 1

Measuring horizontal and vertical angles

Can also measure distances if they have stadia

Question 2

What are the two types of theodolites and what is the difference between them?

Answer 2

Optical: Need to be read manually through an internal microscopic optical system

Electronic/Digital: display readings automatically in digital form

Question 3

What are the three central components of a theodolite?

Answer 3

1) A sighting telescope
2) The horizontal circle
3) The vertical circle

Question 4

List some precautions for theodolite use

Answer 4

Unlock all three lock screws when the theodolite is being taken out of or place in the box

Vertical and horizontal plates must not be turned when screws are in locked position

Make sure the tribrach release lever is in attached position when lifting theodolite

Make sure theodolite is clean, dry before putting back into case

Never force theodolite into/out of case

Use caring handle to handle the theodolite

Close the case as soon as possible and keep it closed

Don’t shoot at the sun

If a filter is used to shoot the sun it should be placed over the objective lens of the telescope NOT in front of the eye-piece

Question 5

What is the precision of most theodolites nowadays?

Answer 5

1” to 0.1”

Question 6

Where are the vertical angles displayed on a theodolite measuring from?

Answer 6

The vertical (ie. they are zenith readings)

ie. when the theodolite is sighting a horizontal, it will display 90 degrees

Question 7

What type of head is necessary on the tripods used for theodolites?

Answer 7

Flat head