Research on dynamic image quality testing methods for space astronomical telescopes

Space astronomical telescopes employ a staring imaging mode. Prior to the telescope's orbital operation, it is necessary to test the dynamic imaging quality of the entire telescope system. To address the challenges in dynamic image quality testing for China's large-aperture, wide-field-of-view space astronomical telescope currently under development, this paper proposes a common-source image-shifting target simulation method based on the mutual collimation principle of the telescope's optical system fields. A synchronized dynamic target simulation optical path was designed for the telescope's focal plane assembly. By utilizing multiple sets of beam splitters and collimating lenses, dynamic targets generated by a single moving source are separately imaged onto the telescope's conjugate focal planes. Leveraging conjugate imaging relationships, these targets are then collimated via planar mirrors and directed back to both the guide sensors on the telescope's lateral sides and the main imaging area. The synchronization of dynamic targets for the guide sensors is ensured by integrating a two-dimensional Fast Steering Mirror (FSM) into the shared optical path. Experimental results indicate that this image-shifting target simulation method achieves: Synchronization accuracy better than 0.5 μm for dynamic targets delivered to both guide sensors and the main imaging area at the focal plane, Actuation frequency exceeding 40Hz for dynamic targets, Energy concentration (REE80) within 30μm×30μm for dynamic targets.