Temporary Adjustments Of Theodolite
Temporary adjustments are a set of operations which are performed on a theodolite to make it ready for taking observations. These include its initial setting up on a tripod or other stand, centering, levelling up and focusing of eyepiece. Initial setting The initial setting operation includes fixing the theodolite on a tripod, along with approximate levelling and centering over the station mark. For setting up the instrument, the tripod is placed over the station with its legs widely spread so that the centre of the tripod head lies above the station point and its head approximately level (by eye estimation). The instrument is then fixed with the tripod by screwing through the trivet. The height of the instrument should be such that observer can see through telescope conveniently. After this, a plumb bob is suspended from the bottom of the instrument and it should approximately align with the station mark. Centering A tribrach with an optical plummet (the black cylinder pointing ...
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Theodolite
A theodolite () is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. The traditional use has been for land surveying, but it is also used extensively for building and infrastructure construction, and some specialized applications such as meteorology and rocket launching. It consists of a moveable telescope mounted so it can rotate around horizontal and vertical axes and provide angular readouts. These indicate the orientation of the telescope, and are used to relate the first point sighted through the telescope to subsequent sightings of other points from the same theodolite position. These angles can be measured with accuracies down to microradians or seconds of arc. From these readings a plan can be drawn, or objects can be positioned in accordance with an existing plan. The modern theodolite has evolved into what is known as a total station where angles and distances are measured electronically, and ...
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