A precise method of monitoring the alignment of two-mirror telescopes, based on a system of synthesized annular holograms

This paper presents the results of a study of the possibility of monitoring the alignment of two-mirror Cassegrain and Ritchey–Cretien telescopes during both fabrication and operation under observatory conditions, as well as in space. The method is based on a system of coaxial synthesized annular holograms as optical compensators and reference optical elements.