Laizhong LDT402AL

　　Sichuan Surveying and Mapping Instrument Company introduces the theodolite Laizhong LDT402AL to you:

　　During measurement,place the theodolite on a tripod,align the center of the instrument with a vertical ball or optical alignment device on the ground measurement station,level the instrument with a level gauge,aim the measurement target with a telescope,and measure the horizontal and vertical angles with a horizontal and vertical dial.According to accuracy,it is divided into precision theodolites and ordinary theodolites;According to the reading equipment,it can be divided into optical theodolites and vernier theodolites;According to the structure of the axis system,it is divided into a repetition theodolite and a directional theodolite.In addition,there is a coded dial theodolite that can automatically record dial readings by coded perforations;An automatic tracking theodolite capable of continuously and automatically aiming at aerial targets;Gyro theodolites and laser theodolites that use the principle of gyro orientation to quickly and independently determine the orientation of ground points;An omnipotent theodolite for astronomical observation with three functions:a theodolite,a meridian instrument,and a zenith instrument;A photographic theodolite that combines a camera with a theodolite for ground photogrammetry.

　　This type of platform has a simple structure and low cost,and is mainly used in conjunction with ground based telescopes(geodesy,bird watching,and other purposes).If used to observe celestial bodies,since the direction of their daily motion is usually not perpendicular or parallel to the horizon,it is necessary to simultaneously rotate both axes and change the rotational speed over time to track celestial bodies.However,other celestial bodies in the field of view rotate relative to the target celestial body,unless a mechanism is added to counteract the rotation of the field of view,Otherwise,it is not suitable for astronomical photography with long-term exposure.