What are the commonly used theodolite models?
The model of theodolite refers to the accuracy of angle measurement, and the specification refers to the code: for example, there are several instruments with different accuracy, such as DJ07, DJ 1, DJ2, D 16. "D" and "J" stand for the initials of Chinese pinyin in geodesy and theodolite respectively, and "07*," 1 ","2* and "6" are seconds indicating the direction observation errors of this kind of instruments. The letters "D" and J07 are usually omitted when writing. J 1 and 12 theodolite belong to precision theodolite, Js theodolite belongs to common theodolite, and 12 and Js optical theodolite are commonly used in construction engineering. The model code of DJ- theodolite mainly includes DJ05, DJl, DJ2 and other models.
The use and working principle of theodolite
Theodolite is the main angle measuring instrument in measurement. It consists of a telescope, a horizontal dial, a vertical dial, a level and a base. When measuring, put the theodolite on a tripod, aim the center of the instrument at the ground station with a vertical ball or optical collimator, level the instrument with a level instrument, aim the measuring target with a telescope, and measure the horizontal angle and vertical angle with a level dial and a vertical dial. According to the accuracy, it is divided into precision theodolite and ordinary theodolite; According to the reading equipment can be divided into optical theodolite and vernier theodolite; According to the shafting structure, it can be divided into retest theodolite and direction theodolite. In addition, there is a coded dial theodolite, which can automatically record dial readings according to coded perforations; An automatic tracking theodolite that can continuously and automatically aim at air targets; Gyro theodolite and laser theodolite that can determine the orientation of ground points quickly and independently by using gyro orientation principle; Universal theodolite for astronomical observation with three functions: theodolite, meridian instrument and zenith instrument; Phototheodolite, who combined the camera and theodolite for ground photogrammetry.
An instrument for measuring horizontal and vertical angles. It was first developed by British mechanic Xisong in about 1730, and was officially used in British geodesy after being improved and finalized. 1904, Germany began to produce glass dial theodolite. With the development of electronic technology, electronic theodolite appeared in 1960s. On this basis, an electronic rapid measuring instrument was manufactured in 1970s.
Theodolite is the mechanical part of the telescope, which enables the telescope to point in different directions. The theodolite has two perpendicular rotating shafts to adjust the azimuth and horizontal height of the telescope. This kind of bracket has simple structure and low cost, and is mainly used with ground telescopes (geodesy, bird watching, etc.). ). If it is used to observe celestial bodies, it is necessary to rotate two axes at the same time and change the rotation speed with time to track the celestial bodies. However, other celestial bodies in the field of view rotate relative to the target celestial bodies, and unless a mechanism to counteract the rotation of the field of view is added, it is not suitable for long-exposure celestial photography.