Control and Image Acquisition of the Dual-FOV Terminal on Lijiang 2.4-meter Telescope

To make full use of the limited interface of Lijiang 2.4-meter telescope's cassegrain focus and improve the efficiency of observation, a dua-field astronomical observation terminal is developed. This terminal will provide different FOV and image scales, and carry out astronomical observation such as rapid photometry and high-resolution imaging, so as to meet the different observational needs of astronomers. According to the requirements of the terminal for the precision of the filter wheel, the switch between the large and the small field optical path, and the speed requirements for the image acquisition of EMCCD camera, this paper uses three-layer closed-loop motor control and multi-thread technologies to realize the precise control of the filter wheel, the FOV switching, as well as the rapid image acquisition and saving of the EMCCD camera. Finally, a detailed test is carried out in the laboratory. According to the results, the control and image acquisition system we designed can meet the requirements of the terminal's performance indicators and functional indicators.