A calibration of the small solar radiotelescope using a new moon

Abstract

Background: Defining the solar brightness temperature at centimetre wavelengths has always been challenging. One of the main reasons has been the lack of a proper calibration source. We carried out observations at 2.7 cm (11.2 GHz) by using the New Moon for the solar brightness temperature calibration. The solar and Moon observations were made using the 1.8-meter radiotelescope operated by the Aalto University Metsähovi Radio Observatory in Finland. In this article, we present our method for defining the brightness temperature of the quiet-Sun level (QSL). Based on these observations, we found 11 500 K±1500 K to be the mean value for the QSL temperature. This value is quite similar which was reported earlier.