Analytical correction of pupil-offset off-axis telescopes with complex figure errors and misalignments based on nodal aberration theory

Abstract

Active optical correction is necessary for space large-aperture optical telescopes, especially for systems with high performance requirements. This paper proposes an analytic correction method for pupil-offset off-axis optical telescopes with misalignments and complex figure errors on the basis of nodal aberration theory (NAT). An analytical description of the wave aberration contribution from the complex surfaces in off-axis telescopes is derived, which gives a unified description for the impacts of the complex surfaces located at the stop and away from the stop. Using the analytical description, a correction model for off-axis telescopes with figure errors and misalignments is established. The off-axis optical telescope with trefoil and astigmatic figure errors and lateral misalignments is taken as a typical example, the presented method is discussed. After the corresponding correction, the perturbed off-axis telescope is almost restored to the system nominal states, which can meet the specification requirements well. Finally, the Monte Carlo simulations are implemented to demonstrate the effectiveness of the presented approach.