Theodolite Surveying | Parts, Uses, Types, Classification
2020年5月15日 · If line of sight of the telescope can be reversed through the rotation of telescope by 180° about the trunnion axis in vertical plane, the theodolite is known as transit theodolite. This type of theodolite is commonly used for surveying .
A theodolite works by combining optical plummets (or plumb bobs), a spirit (bubble level), and graduated circles to find vertical and horizontal angles in surveying. An optical plummet ensures the theodolite is placed as close to exactly vertical above the survey point. The internal spirit level makes sure the device is level to to the horizon. The
This is achieved by adjustment of three foot screws and observing a precise tube bubble. This bubble is known as the plate bubble and is placed on the upper plate.
Spirit level - Wikipedia
A spirit level, bubble level, or simply a level, is an instrument designed to indicate whether a surface is horizontal (level) or vertical . Two basic designs exist: tubular (or linear ) and bull's eye (or circular ).
8.2.8 Altitude Bubble A long sensitive bubble tube called altitude is fixed on the index bar. A mirror is provided to view the bubble when the instrument height is more. The vertical bubble is brought to its centre of its run by adjusting the clip screw at the time of …
Open Access Surveying Library - Chapter E. Bubbles, Axes, and …
Most surveying equipment has a bubble to facilitate being correctly oriented to gravity. Two kinds of bubbles are used: bubble tube and circular bubble. Figure E-1 shows top and side view of both.
the minimum possible movement of the circle or bubble, there is a definitely perceptible movement of the cross hairs over the sighted object. For normal transit theodolites, it is between 20 to 30, while in precise instruments it is about 40 to 80. The magnification is numerically represented as ratio of the focal length of the objective to
Surveying and Leveling: LESSON 15. Theodolite –description of …
The plate bubble is brought to the centre with the help of food screws (in the usual manner). Then the altitude bubble is brought to the centre by means of a clip screw. At this position the line of collimation is exactly horizontal. To measure the angle of elevation, the telescope is raised slowly to bisect the point A accurately.
Spirit level | tool | Britannica
The spirit, or bubble, level, a sealed glass tube containing alcohol and an air bubble, was invented in 1661. It was first used on telescopes and later on surveying instruments, but it did not become a carpenter’s tool until the factory-made models were introduced in the…
Transit Theodolite | Instruments | Surveying - Engineering …
It is also called the bubble line. It is a straight line tangential to the longitudinal curve of the level tube at the centre of the tube. It is horizontal when the bubble is central.