Study On Misalignment And Resolution Detection Of Lyman-α Telescope

As the load of Kuafu A stars, Lyman-α telescope will contain a number of keytechnologies in its development process. The determination of the secondary mirrormisalignment will effect system alignment accuracy; after the alignment completed,resolution detection will provide the basis for imaging and approval systemprediction.This paper used the computer aided alignment method to get the sensitivitymatrix for the secondary mirror offset quantity, but the results shown that thetraditional method was not precise enough. Therefore, the author restructured thesensitivity matrix through the establishment of the relationship between misalignmentquantity-aberration curve fitting, and the calculation results shown that this twotimes sensitivity matrix precision was high enough. The author also built sensitivitymatrix using method of aberration coefficient decomposition, and the results shownthat, this matrix also had a larger error, so the author taken multiple field of view tocalculate the sensitivity matrix using the minimum norm least squares solution,verification shown that the accuracy was greatly improved for the new matrix, andfinally determined by this method was more reliable.After the completion of Assembly, resolution detection was needed. Because thelight source was not121.6nm band, resolution detection can only be carried out withthe visible light, and the detection results of visible light can not reflect the actualsituation in working band, but there was a certain relationship between the two. Thekey to solving the working band resolution lies in solving the mirror surfaceroughness and jitter on resolution error generated in the operation band. In order toestimate the surface roughness of resolution error, based on the theory of linearsystem in Fu Liye, we established the transfer function, and pulled the angle spreadfunction; combined with Lyman-telescope system, we expected the mirror surfaceroughness RMS value was less than2.7nm, effects can be ignored. In order to predictthe effect of jitter on the resolution, we derived the dynamic modulation transfer function, effect of image motion caused by various forms of jitter on the resolutionwas analyzed. According to the detection result in visible light and resolution errorcaused by surface roughness and jitter, we can expected a credible working bandresolution.