A partial 45 MHz sky temperature map obtained from the observations of five ST radars

Abstract
A sky temperature map at 45 MHz covering declination between + 30° and + 60° is presented. The sampling in right ascension is 20 min (~5°) and 2° in declination in most of the map. The originality of the work was to use cosmic emission measurements from five VHF Stratosphere-Troposphere (ST) radars collected during long periods of routine meteorological surveys. This map, which has an accuracy in temperature of about 600 K, is intended first for radar reflectivity calibration and system performance monitoring. The presence of two strong radio sources, Cassiopeia A and Cygnus A, can also serve as the verification of the beam diagram, beam width, and beam pointing direction of the antenna. Finally, this work is an attempt to show the potentiality of ST radar for astronomical purposes.Key words. Meteorology and atmospheric dynamics (instruments and techniques) – Radio science (radio astronomy)