Top panel: emergent fluxes calculated using the model of T_eff = 5777 K, log    g = 4.44, and [M/H] = 0 with iron (log ε_Fe = 7.50, non-LTE with S_H = 0.1, continuous curve) and without iron (dotted curve) compared with the solar flux taken from Woods et al. (1996, dashed curve). The observed flux below 1700 Å is contributed by the solar chromosphere. Bottom panel: the ratio between the non-LTE (S_H = 0.1) and LTE emergent fluxes in the same model atmosphere with log ε_Fe = 7.50 from the calculations with the final (continuous curve) and reduced (dotted curve, see Sect. 2.3) model atoms. For clearer illustration, the theoretical fluxes were convolved with a Gaussian profile of Δλ_D = 2   Å.