High-resolution imaging through atmospheric turbulence: link between anisoplanatism and intensity fluctuations

High resolution imaging with adaptive optics and numerical image restoration processing is now an operational reality for ground-based telescopes. It provides a real-time compensation for turbulence degraded images. However, these correction techniques are only effective in a limited field of view due to anisoplanatism. For endoatmospheric applications, strong intensity fluctuations may also limit the degree of correction. In this paper, we estimate the isoplanatic domain as a function of the degree of correction of high resolution imaging systems and the transition between weak and strong intensity fluctuation regimes. We show that the saturation onset of scintillation corresponds to an isoplanatic field which becomes smaller than the resolution of adaptive optics systems.