A Simplified Pointing Model for Alt-Az Telescopes

Abstract

The telescope pointing model plays a crucial role in characterizing and explaining the inaccuracies in the telescope’s pointing. It uses mathematical models to express these errors and suggests methods to calibrate and rectify them. By employing the pointing model, one can gain a deeper understanding of the discrepancies in the telescope’s pointing accuracy at various positions and orientations. This article introduces the establishment and validation of a simplified pointing model for correcting the pointing errors of an alt-az telescope. The traditional telescope pointing model, with its complex formulas, makes it difficult to quickly apply for the calibration of the telescope’s pointing. This method utilizes two-dimensional surface fitting to obtain the telescope’s pointing error function, enabling a rapid determination of the telescope’s pointing model, which is then validated on the Planetary Atmospheric Spectroscopic Telescope (PAST). Using this method, the azimuth axis and altitude axis errors (root mean square error—RMSE) of the PAST telescope are 6.8 arcs and 3.8 arcs, respectively.