Receiver gain and system temperature instability during the calibration of spectral data at radio telescopes in C-band

The errors arising at the calibration of spectral data from single-dish observations at the radio telescopes of C-band are considered. It was assumed that errors arise as a result of the instability of the receiver gain and system temperature. Theoretical formula for the relative error of the antenna temperature of the source is obtained. Simulation of the calibration process was carried out to verify this formula. The process of observation of methanol masers at the frequency of 6.7 GHz at the Irbene RT-32 radio telescope (Ventspils) was reproduced during simulation. The errors of the antenna temperature of the source arising from observations are estimated.