Application of computer-aided aligmnent to off-axis cassegrain system

The high performance off-axis optical system is generally difficult to align.Many researchers have reported that using sensitivity matrix of some Zernike coefficients is available in alignment.However this method has a weak point in that it generates an accurate result only when the misalignments of component are located within the range where Zernike coefficients are linear to the amount of misalignments.A new method which can solve large misalignments is developed.The application of this method for alignment a diameter 250mm off-axis Cassegrain system produces a measured wavefront error 0.0405λ,atλ= 632.8(?).These results show that this method can calculate large misalignment accurately and has a much better performance than sensitivity matrix method.