The classic Cassegrain telescope has a parabolic primary mirror and a hyperbolic secondary mirror Gallery Tutorial TRAIL: Webel SysML Parsing Analysis example: Optical telescopes from Wikipedia: Structure and port-based light flow model Section Slide kind SysML Block Definition Diagram (BDD)
It is free of coma and spherical aberration at a nearly flat focal plane if the primary and secondary curvature are properly figured. Source Wikipedia
