The 25m Radio Telescope Observing Station

The first VLBI station in China was built in 1986 in a western suburb town of the Shanghai city, called Sheshan. It is a Cassegrain beam waveguide type telescope with a diameter of 25m, and equipped with six receivers at 1.3, 3.6/13, 5, 6 and 18 cm wavelengths. The Sheshan radio telescope has a complete VLBI system including Analogue Base-Band Converter (ABBC), Digital BBC (DBBC), MarkIV formatter and Mark5A recorder, as well as a VLBA formatter with a Mark5B recorder.

Since it started operation, the main task of this telescope is to conduct VLBI astrophysics and geodesy observations. It became a member of the European VLBI Network (EVN) in 1993. Sheshan telescope contributes the longest baseline to the EVN, that is crucial for imaging compact celestial objects. During the past two decades, the Sheshan telescope has been active in international VLBI observation and research. In mid of 2000’s, a high-speed fiber connection was open from Shanghai to Dwingeloo, where the EVN correlator is located, supporting a maximum 1 Gbps data transfer in real time mode.

It has played an important role in VLBI orbit determination for the Chang’e-1 and Chang’r-2 lunar spacecraft. Basic facilities include a 25 m radio telescope system, a microwave laboratory with various measuring and testing equipment, a telescope observation room, and a building for comprehensive experiments.