MODULATION TRANSFER-FUNCTION FOR INFRARED STELLAR SPECKLE INTERFEROMETRY - EVIDENCE FOR A LOG-NORMAL STATISTIC

Measurements of the energy spectra of infra-red images of stellar point sources were made at the Coudé focus of the 3. 8 m telescope at Kitt Peak National Observatory, U.S.A. A scanning slit was used to record the irradiance distribution in the image plane. Experimental results are compared with theoretical models, assuming either a circular gaussian or a log-normal statistic for the perturbation of the complex amplitude of the incoming wavefront. In both cases the telescope central obscuration is taken into account. A good fit is obtained with the log-normal model for the highest scanning rate. © 1979 Taylor and Francis Ltd.