Speckle interferometry with partial adaptive optics correction for big telescopes and the outer scale of turbulence

The influence of the turbulence outer scale on the power spectrum (PS) of speckle interferograms and on the Strehl ratio obtained with low-order adaptive optics (AO) system is examined by numerical simulation. It is shown that the outer scale has a little positive effect the PS when the outer scale magnitude becomes less than the aperture diameter. The finite outer scale has a positive effect on the STrehl ratio of the uncorrected long-exposure image. It is also shown that the Strehl ratio produced by a second-order AO correction is affected quite strongly by the finite outer scale. For the more higher-order correction, the effect under study is very weak and it appears only when the outer scale magnitude becomes less than the aperture diameter.