Example to illustrate how the spectral synthesis was applied to the observed data (in this case the spectrum of the sunlight reflected by the Moon). The three regions investigated are shown within the hatched areas: the molecular head bands around λ5128 (left panel) and λ5165 (middle panel), and the C atomic line at λ5380.3 (right panel). Six spectra computed for different values of [C/Fe] and separated by 0.1 dex are shown. The differences between observed and computed spectra (O−C) are also plotted.