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In order to achieve continuous fine recognition of targets with limited distance, a large zoom ratio near infrared continuous zoom optical system has been designed. Based on the zoom system and its automatic design principle of aberrations, reasonable technical indicators were formulated, the initial structure of the system was determined, and the optical design software CodeV was used to optimize it to achieve a continuous zoom optical system with good imaging quality. The system uses a detector of 4.5-micron $\times$ 4.5-micron pixels, and the field of view is 2.7-degree $\times$ 2.7-degree $\sim$ 12.7-degree $\times$ 12.7-degree, F number is 4.8, using mechanical positive group compensation method, composed of front group, zoom group, compensation group and rear group, including 14 spherical lenses. The design results were evaluated for image quality and the cam curve was solved. The design and analysis results show that the system achieves a continuous zoom of 70-mm~350-mm in the 750-nano $\sim$ 900-nano band. The optical modulation transfer function of the system is better than 0.3 at Ill-lp/mm, the maximum distortion is less than 2%, the image quality is good, and the processing cost is low. The system has the characteristics of large zoom ratio, high resolution, compact structure and smooth zoom curve, and can be used for fine recognition of limited distance targets.

With the development of space optical technology,space camera is required to be characterized by both high resolution of ground sample distance and ability of multi-spectral imaging.Thus the optical system design must be satisfied with the demand of large field of view and small distortion.Based on the on-axis three-mirror-anastigmat system,a new type of optical system was designed,which is characterized by small central obscuration,low optical distortion and reasonable arrangement of panchromatic and multi-spectral CCD.The results indicate that the field angel reaches 1.6°,the system line central obscure coefficient is lower 1/3,the optical system distortion is less than 0.5%,MTF is superior to 0.47 at 50 lp/mm,the image quality reaches the limit of optical diffraction,when the focal length is 12 000 mm,focal ratio is 12,and the spectrum band is from 450 to 900 nm.So the proposed optical system can meet the demand of high resolution multi-spectral space cameras.

Based on the principle of null lens,a new method of error-separation was proposed in null testing.A mathematic model was developed to separate misalignment-induced aberration from the test result.The method was used in the simulations of an off-axis aspheric mirror.The wavefront aberration induced by misalignment is 0.0026λRMS(λ=632.8 nm) after the alignment,compared with 0.2332λRMS before the alignment,which reflects that this method has high accuracy and can improve the efficiency of the null test.

With the development of space technology,small satellite will be widely applied.The paper design a catadioptric system base on Ritchey-Chretion system which including three sphere correction lens.The system has a focal length of 1000,F number of 5,and spectrum band of 450~900 nm,and the field angle reaches 2.3°.the result indicates that,MTF reaches 0.47 at 77 lp/mm with 15% central obscure,the quality of image approaches the diffraction limit,and optical system distortion is less than 0.5%.The system with simpler structure,small size and light weight,can be used in light-small satellite.

In order to improve the imaging quality of optical system, high precision surface of mirrors are put forward to improve their imaging quality. It makes their fabrication harder. Wavefront aberration induced by alignment is analyzed in off-axis parabolic mirror system based on the wavefront aberration theory. The surface error of off-axis parabolic mirror can be compensated by alignment so it will reduce the fabrication difficulty, shorten its period and save its cost. In the simulations of an off-axis parabolic mirror with surface error λ/40 RMS (λ=632.8 nm) ( Root Mean Squre) with ZEMAX software, the figure accuracy is under λ/40 RMS after alignment. It shows that surface error of off-axis parabolic mirrors could be compensated effectively by alignment.