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The Tian Ma Telescope (TM) is the largest fully steerable radio telescope in Asia. It has a primary reflector of 65-m in diameter with a shaped Cassegrain configuration. The primary reflector of the TM is an active surface with 1104 actuators for the 1008 surface panels. The panels of the telescope are divided into 18 rings, and 24 fan sections. Each section includes three sub-sections. The active surface system adopts TCP/IP Ethernet network and RS-485 bus as a dominating mode of communication. The control software works on the Windows system, and adopts the object-oriented technology. The photogrammetry and phase-coherent holography has been used to set the surface to about 0.3mm at the rigging angle. The FEM model is testing now. The Out-of-Focus holography and other techniques will be used to modify the dynamic surface deformation.

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Microwave holographic techniques have been used widely in the radio astronomy area. A new surface diagnosis method based on the phaseretrieval holograph algorithm is proposed. This approach focuses on a novel application of the active deformation. Multiple far-field patterns are measured in focus by adjusting the deformation of the main reflector actively. Using the amplitude of far-field patterns, the phase distribution of the aperture can be retrieved by the phase-retrieval technique. Simulation results demonstrate the feasibility of this method.