OFF-AXIS EXACT RAY TRACING ALGORITHM FOR ZERO COMA POINT DETERMINATION IN CLASSICAL AND NON-CLASSICAL REFLECTIVE TELESCOPES

Abstract

In this work we present a general algorithm to calculate the zero coma point for classical and non-classical reflecting telescopes with aspherical surfaces. We programmed a general ray tracing function applicable to conical surfaces with asphericity, displacements, and inclinations that can be modified by the users, according to their specifications. This function is used to evaluate the transverse coma and determine the optimal conjunction of shift and tilt of the secondary mirror that prevents the introduction of axial coma during the collimation process. We present the calculation of the zero coma point for the classical telescopes of the National Astronomical Observatory, San Pedro Mártir, Mexico. Furthermore, we show an example of a wide-field telescope with aspherical surfaces, as will be the case of the TAOS-II telescopes, for which the classical analytical expression cannot be used.