Measurement of telescope aberrations using phase-diversity method

Atmospheric turbulence and telescope aberrations all contribute to image degradation with ground-based telescopes. For measuring telescope aberrations resulted from atmospheric turbulence, we have developed a method based on phase-diversity technique. The phase-diversity technique is a novel method for reconstructing the object and the distribution of wavefront in pupil plane. Using phase-diversity method, we can independently reconstruct many instantaneous wavefront from pairs of simultaneously recorded focused and defocused images. After that, by averaging these reconstructed wavefront, the telescope aberrations are separated from dynamic wavefront induced by turbulence. The simulation of estimation of telescope aberration using phase-diversity method is conducted. The results show the phase-diversity technique can estimate the telescope aberrations effectively and root-mean-square error is about 0.08 wavelengths.