At a practical level, the N -slit interferometric equation was introduced for imaging applications and is routinely applied to predict N -slit laser interferograms, both in the near and far field. Thus, it has become a valuable tool in the alignment of large, and very large, N -slit laser interferometers used in the study of clear air turbulence and the propagation of interferometric characters for secure laser communications in space. Other analytical applications are described below.