FAST is called the Five hundred meters Aperture Spherical Telescope. This telescope is one of the nine national technology infrastructures reviewed by the National Science and Education Leading Group. It uses the original design of Chinese scientists and the karst in southern Guizhou, China. With the unique topographical conditions of the depression, the construction of a high-sensitivity giant radio telescope with about 30 football fields will maintain the status of world-class equipment in the next 20 to 30 years.
Xiaobian takes everyone to explore the secrets of the installation behind the world's largest radio telescope FAST.
01 address
Since 1994, the engineering name of the new generation of large radio mirrors has gone through several stages of LT, KARST, FAST/SKA, and FAST. Each stage has different site requirements, in scientific goals, technical requirements, and on the platform. At the same time, the requirements of the site are becoming more and more clear. At the same time, the requirements for the scale and shape of the depression are more specific. Based on the specific work of the terrain elevation of the 24 depressions, the typical profile analysis of the terrain and the fitting of the excavation earthwork volume, For the large nests, dozens, and Shangjiachong, the FAST engineering earthwork excavation fitting geographic information system was developed. After determining the sphere radius, the opening radius, the bottom elevation of the spherical cap, and the plane coordinates of the ball center, it can be calculated. Digging the amount of earthwork. The conclusion is that Dawoyu is the best site for building a 500-meter spherical radio telescope.
The picture above shows the FAST innovative design, where:
1—Main reflection surface, 2—feed, 3—Stewart platform, 4—feed tank, 5-suspension, 6—pulley, 7—support tower, 8-winding wheel and servo system
02 installation
The overall performance of FAST is as follows:
Site: longitude 106°E, latitude 26°N, 1000 meters above sea level
Reflective surface caliber: 500 m, spherical crown opening 120 °, spherical curvature radius 300 m
Effective lighting caliber: 300 meters
Maximum zenith angle: 50°
Operating frequency (GHz): 0.3~1.72, 2.15~2.35, 2.8~3.3, 4.5~5.1, (5.7~6.7, 8.0~8.8)
Pointing tracking accuracy: 4 arc seconds
Hoisting: The FAS reflector panel hoisting began on August 2, 2015, and needs to be hoisted 60 meters off the ground. Each triangular body reflective panel has an area of more than 50 square meters. Although the panel is made of aluminum alloy, the weight is up to 900 kg/block. And this similar reflective panel has a total of 4,450 blocks.
Stitching: To be sensitive to the observation of the vast starry sky, the precise positioning of the sub-unit boundaries of the assembled panel is also very important. Scientific researchers have specially designed positioning fixtures, which accurately position the horizontal position and axial height of each panel. The accuracy of each equilateral triangle intersection is maintained at 0.1-0.15mm. Every step of FAST installation work is like 'walking on the tip of the knife'.
On September 25, 2016, the world's largest single-caliber radio telescope FAST was officially launched, and the telescope's scenic spot was put into trial operation on September 26 of the same year. The scenic area includes the FAST Observation Deck, the Astronomical Experience Hall and the Cultural Park.
The establishment of FAST is not only of special value in the field of astronomy, but also has important significance in the field of equipment installation engineering.