An alignment method for the reflective zoom system by applying vector wavefront aberration theory

The image quality of the reflective zoom system is strongly reduced when the position of the mirror is changed during the zooming process. A new alignment method based on vector wavefront aberration theory is suggested in order to surmount this problem during the zoom process. During the three-mirror reflective zoom system zooming process, the secondary mirror plays an active role and the tertiary mirror plays a complementary role. This feature enables adjustment of the tertiary mirror to compensate for the misalignment of the secondary mirror in the zoom process. The alignment of a three-mirror reflective zoom system was simulated. First, we imposed a feeble maladjustment on the secondary mirror as its position was changed during the zooming process. Then, we obtained the compensation values for the tertiary mirror by using the vector wavefront aberration theory. Lastly, the compensation values were imported to be applied to a misaligned three-mirror reflective zoom system. The image quality of the zoom system prior to and after the application of our proposed alignment method validates its correctness and viability.