Average of three spectra of St 2-22 obtained during quiescence in June and July 2017, compared with the spectra from the grid BT-NextGen of the theoretical spectra (Allard et al. 2011, log g = 0.5 dex and T_eff in the range 3300−3600 K). The spectrum of St 2-22 most resembles the giant’s spectrum with T_eff = 3400 K. The spectrum of the atmospheric transmission is shown at the bottom in magenta; it was not subtracted from the observed spectra. It was generated with the use of the TAPAS² service (Bertaux et al. 2014), adopting conditions similar to those during our observations in Sutherland.