The Lijiang 2.4-metre telescope is the largest general-purpose optical telescope in our country and plays a very important role in the field of night astronomy observation as well. This telescope is equipped with a variety of scientific instruments and corresponding observation modes. From the recent distribution time of observation , the spectrum observation of Yunnan Faint Object Spectrograph and Camera (YFOSC) accounts for the largest proportion of the total observation time.Thus improving its spectrum observation efficiency has become the key factor in ensuring the telescope's stable scientific output. In addition, the Nasmyth Focus of telescope is suitable for mounting larger spectrometers. The research and upgrade of the Nasmyth Focus port of the Lijiang 2.4-metre telescope also plays an important role in improving the comprehensive spectrum observation efficiency of the telescope. Starting from the software architecture of the telescope control system, this paper introduces the distributed control system of the Lijiang 2.4-metre telescope, which lays the foundation for improving the efficiency of acquiring stars into slit and the the telescope's closed-loop tracking. The accuracy of extracting stars from image during the telescope closed-loop tracking will affect the accuracy of the closed-loop tracking of the telescope, as well as acquiring stars into slit or fiber accurately, which in turn affects the spectrum observation efficiency of scientific instruments headed by YFOSC. Therefore, several common stars extraction methods are studied and tested in this paper. Experiments show that SExtractor has good adaptability to the Lijiang 2.4-metre telescope. For YFOSC acquiring stars into slit and the telescope closed-loop tracking, in this paper, the point pattern matching algorithm is applied to “gross correction” of acquiring stars into slit and star catalog matching of telescope closed-loop tracking. At the same time, the conversion relationship between the offset of the star in the image plane coordinate system and the fine-tuning amount of the telescope in the horizon coordinate system during closed-loop tracking is also studied. Experiments have shown that，first step is the direct imaging of the YFOSC camera is used to perform "gross acquisition" and "fine acquisition" of the telescope pointing, and in the "gross acquisition", star catalog matching or Astrometry.net matching is selected according to different observation conditions; And then the guide camera is used to perform closed-loop tracking of the telescope. After the actual test, it is concluded that using the new algorithm makes the accuracy of acquire stars into slit increase about 50%, and its speed is reduced about 7 minutes; while the accuracy of telescope close-loop guiding is better than 0.5″ in 1 hour, and the offset of stars on the image plane is not more than 1.8 pixel. For the hardware part of the guiding system, this paper introduces the upgrade of the guiding camera of the Lijiang 2.4-metre telescope. At the same time, in order to improve the comprehensive spectrum observation efficiency of the telescope, this paper also explores the upgrade of the Nasmyth Focus port.
修改评论