Alignment induced aberration fields of next generation telescopes

There is a long list of new ground-based optical telescopes being considered around the world. While many are conventional Cassegrain and Ritchey-Chretien designs, some are from a family of 3-mirror offset field (but still obscured) optical forms that trace back to designs developed in the 1970s. The nodal theory of aberrations, developed in the late 1970s. provides valuable insights into the response of these systems to alignment errors and provides simple, linear solutions to real-time or at-assembly alignment algorithms. The application of nodal aberration techniques to the alignment of two and three mirror astronomical telescopes will be presented.