Alignment metrology for the Antarctica Kunlun Dark Universe Survey Telescope

Dome A is the highest point on the Antarctic Plateau, and the Chinese expedition team was the first to arrive there in 2005 January. It is an excellent site for astronomical observations. The Kunlun Dark Universe Survey Telescope (KDUST), a proposed next-generation Chinese Antarctic optical telescope, is currently being planned. KDUST is a coaxial three-mirror anastigmatic telescope with an entrance pupil diameter of 2.5 m and a field of view of 1.5 0 . The telescope should be fully aligned in order to achieve diffraction-limited image quality. Based on the current optical model for KDUST, in this study we describe a modified alignment metrology and give the preliminary results of numerical simulations. Using the acquisition of field-dependent aberrations, the algorithm, which is based on double Zernike polynomial decomposition and the least-squares fitting method, delivers a suitable set of corrections for resolvingmisalignments including themulti-axismotion of the secondary and tertiary mirrors. Moreover, the algorithm can also be used to calculate the primary mirror’s low-order figure errors mixing with the misalignments of the secondary mirror.