RECURSIVE RELATIONS FOR RAY-TRACING THROUGH 3-DIMENSIONAL REFLECTIVE CONFOCAL PROLATE SPHEROIDS

Modern, large telescopes incorporate segmented primary mirrors, with o ff-axis spheroidal shapes. Each off-axis mirror and the secondary mirr or represent an off-axis optical system without an axis of symmetry an d for which the paraxial optics does not apply. Simple, recursive ray- trace equations are presented that describe exactly a ray propagating through a series of coupled, confocal, prolate spheroids. Vector formu lation using the ray direction cosines is employed for characterizing the ray propagation in different planes through the spheroid axis of s ymmetry.