All Figures

	Figure 1: Photoionization cross section for the third level of neutral Mg (MgI 3 in Table 2) implemented in COSI. The solid line is the original data from the Opacity Project and the crosses are the data interpolated to the frequency grid applied in COSI.
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In the text

	Figure 2: Comparison of ATLAS12 calculation by Kurucz (2005) (dotted line) and COSI calculation (solid line) for H I  410.1 nm (panel  a)) and Ni I  676.8 nm (panel  b)), using the same abundances, atmosphere structure, microturbulence (1.5 km s-1), Gaussian macroturbulence (  km s-1) and rotation broadening (2 km s-1).
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In the text

Figure 3: Panel  a) shows the comparison of the continuum calculated with the ATLAS12 code (dotted line) and continuum plus hydrogen lines calculated with COSI in LTE (solid line), based on identical atmosphere structure and abundances. Panel  b) gives the corresponding synthetic LTE spectra averaged with a 1-nm boxcar. Panel  c) shows the ratio between the COSI and the ATLAS12 calculation, shown in panel  b).

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In the text

	Figure 4: Line opacities for the wavelength range from 200 to 210 nm for the depth point where . The huge number of frequency points necessary to account for the detailed line opacities is reduced to 10 values by means of the ODFs. This allows the inclusion of the line opacities in the NLTE radiative transfer with a reasonable computational effort.
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In the text

	Figure 5: Same as Fig. 3a for the wavelength range 200 to 300 nm (panel  a)), and 300 to 500 nm (panel  b)). The differences are due to different photoionization cross sections implemented in COSI. The lines in panel  b) are the hydrogen lines longward of the Balmer jump.
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In the text

	Figure 6: Same as Fig. 3b plus a comparison with the SOLSTICE measurements (dashed line). The synthetic spectra are convolved with 1-nm boxcar filters to reproduce the resolution of the observation. The higher flux between 210 and 235 nm can be explained by missing continuum and line opacity. The discrepancy between 385 and 390 nm is due to the CN-band not calculated with COSI.
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In the text

	Figure 7: Comparison of the continuum calculations carried out with COSI in NLTE, using the F1999 model atmosphere structure to analyze the effect of the NLTE-ODFs on the calculated continuum.
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In the text

	Figure 8: Comparison of the synthetic spectrum calculated with COSI in NLTE using F1999 as atmosphere structure with the SOLSTICE measurements (dashed line) and the ATLAS12 calculation. The synthetic spectra are convolved with a 1-nm boxcar to reproduce the resolution of the observation.
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In the text

	Figure 9: Comparison of the synthetic spectrum calculated with COSI in NLTE with the F1999 atmosphere structure (solid line) together with the SOLSTICE observation at solar minimum on April 3, 1997 (dashed line).
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In the text