The mutual coherence function (MCF) of the complex amplitude of stellar light waves perturbed by atmospheric turbulence has been determined interferometrically. Results are in good agreement with horizontal laser-beam determinations. Stellar measurements provide quantitative estimations of seeing conditions for astronomical observations.
C. Roddier and F. Roddier, "Correlation measurements on the complex amplitude of stellar plane waves perturbed by atmospheric turbulence," J. Opt. Soc. Am. 63, 661-663 (1973)