On the Adjustment of the Polaraxis of an Equatorial Telescope

The pointing accuracy and the tracking accuracy are important indicators to evaluate an astronomical telescope.As for an equatorial telescope,they are affected by the alignment accuracy of the polaraxis.It is crucial to mount the polaraxis properly,and the axis calibration is also rather important.This paper introduces a method to calibrate the polaraxis alignment by using reference stars.Particularly,we give an analysis to reasonably choose reference stars.We conclude that reference stars need to be on the meridian plane when the east-west direction of the polaraxis is adjusted,but need to be on the 90° hour-circle plane when the pitching direction is adjusted.After several alternate adjustments in the two directions,the polaraxis of the telescope can be accurately aligned.