Example of HARPS-N spectra and selection of regions for measurement. Background thin black line: Göttingen solar flux atlas (Reiners et al. 2016). Its higher spectral resolution is evident from its deeper line profiles. Blue line: Average over 100 HARPS-N exposures. Red line: Selected regions of Fe I line absorption. Green line: Selected reference regions of quasi-continua. Thin brown line around 100%: ratio between one representative HARPS-N exposure and a 100-exposure average, illustrating the random-noise level for a single exposure with nominal S/N in grating order 50 equal to 430. The wavelength scale represents values in air (vacuum values in the Göttingen atlas were converted to those in standard air).