Fan Qing-yuan

Sub-reflector model depending on elevations and performance evaluation for TM65 m radio telescope

A sub-reflector system of the TianMa 65 m radio telescopes has been installed in order to compensate for the gravitational deformation of the sub-reflector support and the main reflector. The position and attitude of the sub-reflector are variable in order to improve the pointing performance and the efficiency at different elevations. A model has been constructed to determine the position and attitude of the sub-reflector with elevation. Test results show that the sub-reflector model can effectively improve the efficiency of the 65 m radio telescope at both high and low elevations, where the efficiency can be improved by 20% and 15%, respectively. At X band, the aperture efficiency of the radio telescope reaches more than 60% over the entire elevation range. Pointing deviations caused by the sub-reflector model are consistent with the grasp simulation results.

Determination of angular diameters of 4 stars

Abstract The angular diameters of 4 stars, SAO 109718, 092556, 128427 and 098755, are reported, which are obtained from photoelectric observations taken during the events of lunar occultation of the 4 stars. The results are listed in Table 2 and the light curves and the corresponding fitting ones for the stars are shown in Fig. 1–4, respectively.