Analysis of the Image-Field Rotation in the Auto Guide System of the 1-meter Infrared Solar Telescope of the Yunnan Observatory

The Auto Guide System of the 1-meter infrared solar telescope YNST is a high-precision feedback tracking system,which is based on the detection of the offset of the solar image on the CMOS Image Sensor Array to set the feedback control signal for the control system. As the YNST is an altazimuth mounting telescope, there is an image-field rotation in the detected offset of the solar image. In order to obtain clear solar image, there is a need to eliminate the image-field rotation to achieve the tracking requirement of the Auto Guide System. In this paper, based on spherical astronomy,astrometry,and the knowledge of the optical system of the guide telescope, we derive and analyze the variation pattern of the image-field rotation.