Wave Aberration Correction Algorithm for Unobscured Two-Mirror Telescope Designs

In the present work, we propose a simple analytical algorithm for unobscured two-mirror telescope designs. It is based on fitting of the closest aberration-free surface for each field position and allows for computation of the wave aberration distribution over a large aperture. All the equations necessary for the algorithm implementation are expressed in a general form allowing its application for complex freeform mirrors. It is shown using the example of a small telescope with f′=245 mm, F/#=7 and 2∘×0.96∘ field of view, that the algorithm allows us to find a good starting point, and reach a high spatial resolution in comparison with off-axis Ritchey–Chrétien and Schiefspiegler telescopes. The algorithm can be of a specific interest for the development of highly specialized imaging systems of several types.