Long Focal Length Vacuum Aberration Measurement And Calibration Method Collimator

With the development of space optics, the demand of the instruments such as astronomical telescopes and space cameras has been increased. So the higher performance of the corresponding optical test system is necessary. The aperture and focal length of the vacuum collimator, which is the main component in the optical test system, become much larger. The collimator optical system is mainly evaluated by measuring its wavefront aberration and calibrating its focal plane and the focal length, and their key technologies are researched in this paper.The design results of the vacuum collimator withΦ1m diameter and 30m focal length have been presented, and also its optical performance parameters. The value of RMS is better thanλ/50 in the centerΦ60mm of the focal plane in the system. When in 40 mm-1, the largest space frequency, the value of MTF can be promised to be better than 0.2. The wavefront aberration of the vacuum collimator withΦ580 mm diameter and 12m focal length has been measured separately by the collimator method using the interferometer under the conditions of normal temperature and normal pressure, normal temperature and low pressure, low temperature and low pressure. In all of above statements, the value of PV is better thanλ/2 and the value of RMS is better thanλ/20. The present point method has been proposed to measure the wavefront aberration under the conditions of low pressure and normal temperature. Gauss eyepiece method and the pentaprism scanning method have been used to calibrate the focal plane of collimator with 2m focal length. The precision is±0.02mm with later method and is better than the first. The focal length of the collimator with 5m focal length has also been measured, and the result accords with the results calibrated before. As a result, the feasibility of calibrating the focal length of a long focal length collimator with the Perot board has been verified.