Abstract: A large, low cost and high quality optical telescope system (1) includes a segmented primary mirror (2) having a plurality of spherical mirror segments (3) arranged in a non-spherical shape (4), a parabolic shape in the disclosed embodiment, so that the rays incident upon the individual spherical mirror segments stay separated at an exit pupil (5) of the system, allowing for correction of aberrations. A discontinuous pupil corrector in the form of a segmented mirror (7) having a plurality of aspheric correction terms in it, is located at the exit pupil for correction of aberrations introduced from respective ones of the plurality of spherical mirror segments of the primary mirror. The discontinuous pupil corrector preferably is a segmented deformable mirror. The telescope system and related method can achieve diffraction limited performance for very large systems. The disclosed embodiment is a 35 meter aperture, deployable space telescope system.