Computer aided alignment for a Cassegrain telescope

In order to further improve the property of an optical system, the precision alignment is required. Computer-aided alignment (CAA) has been studied to complete the challenge. In this paper, we report an application of computer-aided alignment in a Cassegrain telescope based on wavefront errors and have analyzed the character deeply. The principle of CAA is establishing the mapping relation between the misalignments and the wavefront errors. Here, a Cassegrain telescope is built up in ZEMAX. And, the inverse sensitivity analysis of the optical system is done to select the corresponding fringe Zernike polynomial coefficients. MATLAB and ZEMAX are connected through Dynamic Data Extension to make up the simulation platform. Then, the misalignments are calculated by CAA in different cases. Especially, the closed loop simulations are done in two cases, PM with surface errors and PM without surface errors. The simulations demonstrate that the calculation precision of CAA is high in a large range of the misalignments, and it is still available to align the optical system rapidly and precisely while PM has surface errors.