Data acquisition system in the LLMC

摘要

Two data acquisition systems of the Lower Latitude Meridian Circle (LLMC) are described in this paper, of which one is based on a video CCD and the other is based on a scientific CCD. To determine the position of a celestial body absolutely and precisely, the LLMC is equipped with several precision measurement devices such as one precision clock, nine Reticon linear photodiode arrays, one video CCD, one scientific CCD, one rotary inductive synchronizer, and one grating linear displacement transducer.