For the effective application of the radio astronomical method for measuring the gain of large antennas, the problems of discrepancies in the flux densities of the main calibration radio sources (supernova remnants Cassiopeia A and Taurus A and the radio galaxy Cygnus A) according to data from different catalogues are analyzed, as well as taking into account their angular sizes and structure. A comparison of the data on the characteristics of these radio sources obtained at the Nizhny Novgorod Research Institute and other radio astronomical observatories over several decades is carried out.
Dugin et al. (Wed,) studied this question.