Lenghu Town is located in Mangya City, Haixi Mongolian and Tibetan Autonomous Prefecture, Qinghai Province. On an autumn night, the vast Gobi Desert is sparsely traveled. Looking up, the starry sky is bright, and the Milky Way is far away. It seems that along this bumpy dirt road, one can enter the Milky Way and step into the stars. The beautiful scenery is intoxicating. In the area C of Saishiteng Mountain, 4200 meters above sea level, Jiang Ji'an, professor of the Department of Astronomy of the University of Science and Technology of China, Lou Zheng, chief engineer of the Qinghai Observatory of the Zijinshan Observatory of the Chinese Academy of Sciences, and other scientific researchers have no time to enjoy it. They sit in the workshop of the Mozi Sky Survey Telescope jointly developed by the University of Science and Technology of China and the Zijinshan Observatory of the Chinese Academy of Sciences, staring at the neatly arranged computer screens, Keep an eye on the working status of the telescope at all times. The Mozi Sky Survey Telescope is the equipment with the strongest optical time domain sky survey capability in the Northern Hemisphere, and can survey the entire northern celestial sphere once every three nights. On September 17th, the Mozi Sky Survey Telescope, which had been in operation for a month, was officially put into use and the first "assignment" - a picture of the Andromeda galaxy - was handed over. Chang Jin, Vice President of the Chinese Academy of Sciences and a member of the Party Leadership Group, said, "Mozi Sky Survey Telescope can help us accelerate more original breakthroughs in the field of astronomy, actively seize the scientific and technological commanding heights in the field of astronomy, and make greater contributions to the self-reliance of high-level science and technology." Mozi Sky Survey Telescope, a telescope used to record stars, is a "big guy" with a height of 10 meters and a weight of 50 tons. Chief designer Kong Xu, a professor at the Astronomy Department of the University of Science and Technology of China, picked up a bamboo pole and pointed it out to the reporter, introducing: Its main mirror has a diameter of 2.5 meters, a middle hole of 0.76 meters, a thickness of 0.12 meters, and a surface flatness of better than 8 nanometers. The active optical support of the main mirror adopts an axial pressure type 54 point support, with an observation band of 320 nanometers to 960 nanometers, a field of view diameter of 3 degrees, and an image quality of up to 0.4 angular seconds. The energy concentration is better than 80%. You may not understand, but in simple terms, it is very excellent! "An observatory was built at an altitude of 4200 meters, It's not an easy task. "The altitude, pressure and temperature changes here are different from those in low altitude areas, and there are special requirements for instruments. For example, ordinary hard disks cannot be used here, and the CCD camera, the core equipment of the telescope, must be able to work stably at minus 100 degrees Celsius." Kong Xu said that during the manufacturing process of the Mozi Sky Survey Telescope, the University of Science and Technology of China, the Zijinshan Observatory of the Chinese Academy of Sciences The Institute of Optoelectronics Technology of the Chinese Academy of Sciences and other leading scientific research forces have assembled to break through many technical bottlenecks. For example, we have conquered the 2.5 meter large aperture thin mirror technology and achieved axial positioning error of the main focus device within 2 micrometers through the use of active collimation technology and active correction technology of the main mirror shape. We have also achieved real-time correction of gravity and thermal deformation of the main mirror, and controlled the wavefront error within 6 nanometers; The technology of high-precision CCD splicing with large focal plane and ultra-low noise and low-power readout and driving has also made progress × The 9K scientific grade CCD chip is spliced, with a flatness of less than 20 microns, which is thinner than hair. These "skills" make the Mozi Sky Survey Telescope the "strongest in the Northern Hemisphere", not only able to record the starry sky in real-time, but also able to see previously difficult to observe, very dark celestial bodies. Kong Xu said, "We took 30 seconds to shoot