... record and characterize EM radiation, one needs, at least, a camera, that will focus the approximately plane EM waves arriving from a distantsource, and a detector at the focal plane of the camera, ... geometricaloptics, with a central spot having an angular radius (in radians) ofθ = 1.22λD. (1.1)Consider, for example, the image of a field of stars obtained through some camera,and having also ... examined, analyzed, and disseminated among other researchers. Astronomicaldata are almost always saved in some digital format, in which they are most readilylater processed using computers. All telescopes...