天体测量技术及应用研究组知识库

A new astrometric telescope, Multi-Function Astronomical Transit, has been built in Yunnan Astronomical Observatory. Its main imaging device is a digital CCD camera without refrigeration because the telescope is only used to observe stars brighter than 7.5mag. As an astrometric telescope like the Lower Latitude Meridian Circle, some special errors from the horizon and the altitude axis of the telescope must be measured. Thus two analog CCD cameras are used. The digital camera is connected to a digital frame grabber via a Camera Link cable and a custom-made cable, while the two analog cameras are connected to an analog frame grabber by two custom-made cables. The two frame grabbers are separately mounted in two image workstations and operate in external trigger mode. Two trigger signals are generated by the telescope control system, one for the digital camera, another for the two analog cameras. The software of image acquisition is programmed using VC++ and Sapera LT. This paper presents an imaging system solution for the new transit, programming methods and the test observation results.