Examples of polar (red line) and equatorial (green line) brightness temperature profiles derived from solar images obtained through the Grueff Radio Telescope and SRT. Top: profiles derived on September 6, 2020 from the 18.3 GHz (left) and 25.8 GHz (right) Grueff Radio Telescope images. Bottom: profiles derived on January 28, 2020 from the 18.8 GHz (left) and 24.7 GHz (right) SRT images. Typical errors in the brightness profiles are in the 5–20 K range, significantly affecting only the outwards tails. Blue dashed lines indicate the solar radius at the photosphere level R_⊙,opt = 959.16 ± 0.19 arcsec (Mamajek et al. 2015; Prša et al. 2016; Haberreiter et al. 2008).