Cross-sections of H₂O, OH, Fe, and Mg in the wavelength range of NIRPS. The cross-correlations are calculated at a pressure of 1 mbar and a temperature of 2500 K. H₂O contains a forest of lines throughout the entire wavelength range shown here. OH is prominent at wavelengths longer than 1.4 μm but still has strong lines around 1 μm. Fe features are mostly present in the shorter wavelengths, with its most important lines below 1.2 μm. Mg has only a few lines overall.