الخلاصة

The aim of the research is to construct tables for the photon counting through the output current of the detectors which produced by the luminous flux arrived from stars of various magnitudes by using UBV filters at two observational systems at international observatories , where the relations of flux and current as well as the relations of photon counting which were deduced through the research. The tables can be used as a guide for the observer to determine the efficiency of data that registered by the observational system and to ensure the safety of the observations