What is a theodolite?
Theodolite is used in construction, topography, geodesy and in many other areas where accuracy is very important. Like the name of the device, and its applicability so far, we are completely unclear, if not yet had to use it. Even greater mystery is the structure of the device. These devices are divided into two categories: optical and electronic.
In the optical device on the lenses there are counting points, which allow calculating the coordinates. The electronic version has a display and a function for storing coordinate points. To understand how the device works, let's look at the theodolite structure.
Theodolite is a U-shaped instrument on a stand with a telescope. The main parts of the theodolite with which the work is carried out are: a horizontal circle, a telescope, a vertical circle, a cylindrical level, and 3 lifting legs.
The basic elements of the theodolite and their functions
Now consider these parts in more detail. The horizontal circle has two components: the limb and the aliad( this is the entire rotating part of the device).The theodolite's limb has an important function. It marks the division, and on the aliad - the counting devices. The attached scheme of the theodolite will help visually to present all these parts and their work.
The limb and the aliad can be used separately from each other. If it is necessary to measure several angles of the same height, the limb is fixed in the desired position, and the aliad can be rotated depending on the need. The rotation of the axes of the aliad and limb is so important in the device that they are called the main axes of the theodolite.
If the aliad and limb are viewed together with the telescope, they are called the main nodes of the theodolite. In order to measure the angle, it is necessary to place the center of the horizontal circle above the measured angle. The optical centering device will help to do this.
To prevent the theodolite telescope from moving to the side, all movable parts in it are fixed using clamping and guiding screws.
What role does the vertical circle of theodolite play? He also has his limb and aliada. With its help, the projection of vertical surfaces is measured. Angles above the horizon are called positive, and angles below the horizon are called negative angles.
How to use theodolite correctly?
How to understand if the correct point of the measuring angle is correctly fixed? Each theodolite has levels. It is important to set them precisely during installation. Adjustment of the screws will help to reach the desired level. The optical centering or plummet fixes the accuracy of the center of the limb.
Knowing what theodolite consists of, you can begin to practice. How can I use this device? To start the with the , place it on a tripod, and select two anchor points. They are guided by a telescope of theodolite.
We aim the visual tube at point "A", fix the device and measure it with a vertical thread. The horizontal circle is counted, and the data is recorded in the log. The fixation is removed, and the second point is tracked, let's call it "B", turning the device clockwise.
The next step is to transfer the pipe through the zenith. We change the position of the circle and point the telescope to the point. With small discrepancies in the measurement, the average number is correct. The value of the limb in the measurement must be zero or close to zero. The aliad rotates until the strokes of zero values on the microscope and the limb coincide. All measurements are made in a circle.
