AbstractOver the last two decades, an extensive body of knowledge has been developed concerning the effects of atmospheric turbulence on optical propagation. Much of this is directly relevant to astronomical imaging, and with proper interpretation, to the type of pseudo-imagery that is of concern to us at this conference. This paper will provide an overview of this matter, hopefully with sufficient insight developed that the reader will be able to quickly estimate the nature and magnitude of the turbulence effects to be expected in a pseudo-imagery process. The paper starts with a review of turbulence effects on conventional imagery, reviewing the “nondimensional” nature of the turbulence statistics, presenting the local measure of the optical strength of turbulence,, and developing the resolution scale, r0. It presents a statistical view of the nature of the wavefront distortion geometry, indicating the dominance of the random wavefront tilt component. The MTF for conventional imagery and for speckle interferometry (Labeyrie) is presented with comments concerning their relationship. Following that, the foundation of the speckle imagery concept (Knox-Thompson) is presented. Results are then set forth for the allowable spectral bandwidth in speckle techniques, as well as results defining the allowable field-of-view size (isoplanatism) and the allowable exposure time for speckle techniques. Taken all together, these results provide a basis for estimating most of the significant effects of atmospheric turbulence in speckle interferometry and speckle imagery.
The Nature of Atmospheric Turbulence Effects on Imaging and Pseudo-Imaging Systems, and its Quantification
