LEVELLING INSTRUMENT
Level is an instrument used in establishing horizontal line. it uses spirit babble tube with the construction of telescope, you can sight or object aid also focus, line of sight is called line of collaboration. Basically there are 3 main types of level or leveling instrument.
Each instrument have a few basic parts the working of which will be firmly under store. Hide are dumping level, tilting level, automatic level. Each is used in sighting different ways.
DUMPING LEVEL
This is the most common form of survey level and it consist of able tube attach to the telescope.
The telescope is rightly fixed to the stage which has 3 or 4 foot screw.
The foot screw used to bring the babble to the centre of its run and also to make axis of the babble horizontal. If the line at collimation is parallel to the able axis then the line of collonation is horizontal. The advantage was in the fact that when it is leveled, you can sight all the direct – this instrument is getting out of the ………………….
TILTING LEVEL
Is an improvement of the dumping level, instead of being tilted. When using this instrument it is only necessary to set it roughly leveled. As babble is finally leveled for each reading by means of adjusting screws ad thus greater accuracy is obtained. Since the babbles axis is always mark to be right angle with the axis however the adjustment is done before every reading.
AUTOMATIC LEVEL
Just as the name implies, it is an automatic instrument. the instrument may be out of adjustment if the recticle is mis-position after carrying out the task as described for titling level.
In automatic level, the horizontal hair is brought to the correct readings by MV of recticle.
The instrument has circular spirit babble you don’t have to set the babbles every time. It also gives direct image instead of inverted images.
Along with any of the above 3 types of level we can also use level staff, staff plate or cross-foot especially when we are on soft ground.
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