Speckle interferometry measurements of atmospheric nonisoplanicity using double stars*

Abstract

The parameter characterizing nonisoplanatic effects in speckle interferometry can be measured by observing double stars. An experimental method is developed which permits estimation of this parameter in the presence of inherently large photon and detector noises as well as unequal double-star component brightnesses. Data are presented on five double stars ranging from 0.22 to 3.48 arc sec in separation. The results are compared to theory and the implications to both speckle interferometry and compensated imaging are discussed.