If you make a telescope with a lens with a diameter of two meters and a five meters and a sensor with 720 million pixels, how far can it see? How clear will it be to see things?
In fact, the mainland is currently building one such telescope, which is a large field of view sky survey telescope built by the University of Science and Technology of China and the Haixi Mongol and Tibetan Autonomous Prefecture of Qinghai Province at the Astronomy Observatory site in Lenghu, Haixi Prefecture, Qinghai Province (one of the best astronomical observatories sites in Asia and the Eastern Hemisphere), whose full name is the University of Science and Technology of China - The Chinese Academy of Sciences Purple Mountain Observatory Large Field Survey Telescope, English name Wide Field Survey Telescope, referred to as WFST, It is a new generation of astronomical surveying telescopes being developed by the mainland, a major national astronomical observation infrastructure, and will become the optical time domain survey telescope with the strongest ability to survey the sky in the northern hemisphere after completion.
According to the news from the University of Science and Technology of China on April 11, the research team composed of the university and the Purple Mountain Observatory of the Chinese Academy of Sciences has completed the development of the main mirror CCD290 camera and CCD test system, and the relevant results have been published in the internationally renowned astronomical instrument journal "Journal of Astronomical Telescope Instruments and Systems", this innovative research result has laid the foundation for the development of the main focus camera of the large field of view telescope.
Large field of view sky survey telescope is a new generation of astronomical telescopes developed by the mainland, its main mirror aperture of 2.5 meters, the design of the use of the international leading main focus optical mode, can provide large field of view, high precision and wide band of sky survey capabilities, its photosensitive element is a large area array 720 million pixels spliced CCD detector, by 9 CCD290-99 chips spliced together, imaging array reached 9K x 9K, imaging area of 92.2 mm × 92.4 mm, with ultra-low noise readout capability, The readout noise at a readout rate of 500Kpix/s can be less than 5 electrons.
In the middle of the image above is the main focus camera, and on the right is the CCD290 camera
The main focal camera with these two main accessories is the main equipment of the telescope, accounting for 1/3 of the entire telescope, in addition to the curvature sensor and the guide star sensor for active optics, these equipment forms the telescope's powerful sky survey observation capability, it is also the first domestic, international leading large field of view main focus camera, this survey telescope can tour the entire northern hemisphere every three nights.
Some people call the large field of view sky survey telescope as "another Chinese sky eye", indeed both have a strong sky survey observation ability, but the two are very different, in the way of observation, the Chinese sky eye (FAST) will not move, basically with the rotation of the earth to tour the night sky, can not fix the perspective at a certain point in the night detailed observation, but WFST can dynamically tour the night sky, can be a fixed point on the sky for a long time observation.
Schematic diagram of the WFST structure
The electromagnetic spectrum of the two observations is also different, FAST is a telescope in the radio band, the electromagnetic wave bandwidth is much wider, and the WFST is a pure optical astronomical telescope, which belongs to the astronomical observation of the visible light field.
Chinese Sky Eye
As the most powerful large-field optical sky survey telescope in the Northern Hemisphere, WFST is a powerful main focus camera with "scientific imaging, wavefront detection, and guide star sensing". It can find countless galaxies, quasars and stars in the huge cosmic space, and can also monitor large celestial collisions, supernova explosions, stellar helium flashes, fast radio bursts and other temporary sources in the distant universe, as well as variable star objects such as the Milky Way and nearby galaxies, small celestial bodies such as asteroids and comets in the Kuiper Belt in the solar system, and can also judge the structure and formation and evolution history of galaxies by observing the Milky Way and the flow of stars in nearby galaxies.
Resources:
China Science Daily April 11 article "Large Field Survey Telescope Scientific Imaging Detector Test Platform Completed"