Search results
Results from the WOW.Com Content Network
The pibal theodolite uses a prism to bend the optical path by 90 degrees so the operator's eye position does not change as the elevation is changed through a complete 180 degrees. The theodolite is typically mounted on a rugged steel stand, set up so it is level and pointed north, with the altitude and azimuth scales reading zero degrees.
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 fundamental lines or axis of a transit theodolite include the following:- Vertical axis; Axis of plate levels; Axis of telescope; Line of collimation; Horizontal axis; Axis of altitude bubble and the vernier should read zero. These adjustments once made last for a long time. These are important for accuracy of observations taken from the ...
The alidade is the part of a theodolite that rotates around the vertical axis, and that bears the horizontal axis around which the telescope (or visor, in early telescope-less instruments) turns up or down. In a sextant or octant the alidade is the turnable arm carrying a mirror and an index to a graduated circle in a vertical plane. Today it ...
Normal-section azimuth is the angle measured at our viewpoint by a theodolite whose axis is perpendicular to the surface of the spheroid; geodetic azimuth (or geodesic azimuth) is the angle between north and the ellipsoidal geodesic (the shortest path on the surface of the spheroid from our viewpoint to Point 2).
The instrument was paid for by the Crown and the King immediately presented it to the Royal Society; for this reason the theodolite is designated as the Royal Society theodolite, or Ramsden RS in short. There is a complete description of this theodolite in the final report of the Anglo-French Survey (1784–1790). [4]
A total station or total station theodolite is an electronic/optical instrument used for surveying and building construction. It is an electronic transit theodolite integrated with electronic distance measurement (EDM) to measure both vertical and horizontal angles and the slope distance from the instrument to a particular point, and an on ...
Unlike an artificial horizon or inertial navigation system, a gyro-theodolite cannot be relocated while it is operating. It must be restarted again at each site. When available, astronomical star sights are able to give the meridian bearing to better than one hundred times [citation needed] the accuracy of the gyro-theodolite. Where this extra ...