Page 25 - ebook_soil engineering practical workbook_15112021
P. 25
- Recheck the fine adjustment if necessary. If there is not enough
adjustment in the levelling screws, then the theodolite table is not level
enough and you will have to adjust the leg heights until it is.
2.5.3 Focussing
- After the centering and levelling, parallax should be removed for
accurate work. It can be done by first focussing the eye piece and then
focusing the objective of the telescope.
- Remove telescope cover and focussing the eye piece of telescope until
the cross hair is bright and sharp. Point the telescope to any distant
targets. Then focussing the objective until get the target looks sharp.
17 | Soil Engineering Practical Workbook
