Study Of The Target Simulator Used For The Optical Rectification And Testing Of The Follow-up Optical Path

The precision requirement of the space optical system such as Space Camera and Space Telescope is constantly increasing, and its applied area is continuously expanding. In order to test the optical properties of the space optical systems, it is necessary to develop the matched target simulator. In this paper, the optical system design for a certain space camera exclusive target simulator, the manufacturing and testing for the primary and secondary mirrors and the alignment of this system are studied.According to the design specifications of the target simulator working at 0.3μm～15μm wavelength with 250mm diameter,1700mm focal length, and the aberration specification of typical reflective optical system, the optical configuration of off-axis R-C system has been chosen. The overall scheme of the optical system is designed. The initial structure of the system is calculated. The design result is optimized by ZEMAX software. The image quality of the designed system is analyzed and evaluated. The results show that the RMS values of the wavefront aberration under the following field of view(FOV),0’, ±5’, ±10’,±12’and ±14’, achieve λ/19, λ/21、λ/17、λ/16 and λ/10 respectively, which satisfy all of the design requirements.According to specification of the primary mirror with 270mm diameter,270mm off-axis distance, the Offner compensation method is used to test it. And the Offner compensator is designed and optimized by using ZEMAX software. The RMS value of the primary mirror’s wavefront aberration is λ/40 using this compensator which meets the requirement for the primary mirror’s quality. For the secondary mirror with 110mm diameter and 90mm off-axis distance, the off-axis Hindle method is selected to test it. The Hindle sphere with 550mm radius of curvature and 612mm diameter is chosen according to the calculation of initial solution. The RMS of the secondary mirror’s wavefront aberration is λ/62.5 with this Hindle sphere. So the secondary mirror conforms to the requirements of manufacture.The installation and adjustment of the system is completed by means of the theodolite, knife-edge tester and interferometer. We obtained that the RMS value of wavefront aberration at the axial and ±5’FOV is better than λ/15, the RMS value at the ±10’FOV is better than λ/13, the RMS value at the ±12’FOV is better than λ/10 and the RMS value at the ±14’FOV is better than λ/8. All of these comply with the design target. Then how the primary and secondary mirror affect on the image quality of the system when they tilt and rotate is analyzed. The target simulator is finished.