Numerical Simulations of Astronomical Imaging with the Phase-Screen Method

In this paper we present a study of simulating turbulence-influenced phase screens. Effects of inner and outer scales of turbulences on phase screens in simulating with different Monte-Carlo methods are analyzed. Our result shows the effectiveness of the SH-FFT method under certain specific astronomical observational conditions. By using multiple-layer model of atmospheric turbulences (corresponding to multiple phase screens), we introduce a new method for simulating astronomical images of short and long exposures. Using the new method, we simulated images of a point source with and without the correction by an AO system.