Relative deviation of the NESSY spectrum from the one calculated with COSI. COSI spectrum is available only from 90 nm onward. (NESSY − COSI)/COSI ratio is shown for the three consecutive changes in the code that had the largest impact on the resulting spectrum: the update of ALI-scheme (ALI), implementation of the new hydrogen collision coefficients (ALI + COL) according to Johnson (1972) and the correction of an error in the treatment of the reaction (C.1)(ALI + COL + C.1). All spectra have been calculated using the FAL99-C model of solar atmosphere (Fontenla et al. 1999) and smoothed with the ATLAS3 Gaussian (see Sect. 4) on a 0.5 Å resolution grid. The shaded part of the spectrum was not published by S2010. Note the logarithmic scale of the x-axis in the bottom panel.