Experimental estimation of the spatial-coherence outer scale from a wavefront statistical analysis

Abstract

Estimations of the spatial-coherence outer scale L 0 relevant for high angular resolution imaging are deduced from measurements of both angle-of-arrival normalized covariance and difference of the variances measured with two different size circular apertures. These measurements have been obtained by means of an experimental device identical to a differential image motion monitor. Simultaneous estimations of Fried's parameter r 0 are obtained from this difference and compared to those deduced from the structure function (ESO's DIMM method). The sensitivity of these techniques to the different noises as well as to the model describing atmospheric turbulence, is deeply analyzed and discussed