The 65-meter radio telescope is an astronomical observation device developed by 54th institute and my company serve for the Shanghai Observatory of the Chinese Academy of Sciences. It is the largest antenna with the highest aperture and accuracy in Asia. It is mainly used in deep space exploration and VLBI orbit determination.
 

Project Overview
 

The 500m aperture spherical radio telescope uses the dimpled surface in the Karst area of Guizhou province as a telescope site to build the world's largest single-caliber radio telescope, which has a big receiving area as large as 30 standard football fields. . The FAST project is about 10 times more sensitive than the 100-meter telescope in Bonn, Germany, which was known as the "biggest ground machine in the world". Compared with the American Arecibo 300-meter telescope which was named "The First of the 10th Mankind Project of the 20th Century," the overall performance is about 10 times improved; FAST’S mission is to explore the neutral hydrogen in the universe, observe pulsars, leading the international low frequency very long baseline interferometry network, detect interstellar molecules, and search for possible interplanetary communication signals.

65 meter radio telescope
 

The 65-meter telescope uses a modified Cassegrain antenna with a 65 meters aperture , a 70 meters height and a approximately 2,700 tons weight. It can work in the eight frequency bands L, S, C, X, Ku, K, Ka and Q. The bottom working frequency is 1.25 GHz and the maximum operating frequency is 46 GHz. S/X and X/Ka are dual frequency simultaneous observations, and the antenna pointing accuracy is better than 3 arc seconds. With actuator, the working accuracy of the main reflector is less 0.3mm ,0.6mm without. The working accuracy of the subreflector is less than 0.1mm and its adjustment adopts Stewart parallel mechanism, which can accurately correct the error of its position.

The 65-meter antenna should maintain high surface accuracy under different angles of pitch. In the design stage, the 65-meter antenna structure performs mechanical simulation analysis using finite element technology under various working postures, only the technical specifications such as stress, strain, resonance frequency, etc meet the requirements the optimal topology and cross-section parameters are obtained.

For the first time, the 65-meter antenna has adopted the all-orbit welding technology in China. The track is made of 42CrMo material. The maximum height difference after welding is less than 0.5mm and the surface hardness is HRC48~HRC52.