Correction of H₂O tellurics. Top: residuals from telluric correction with TAU and molecfit on the validation observation for tellurics in order 54. Bottom: combined residual in the same spectral region from correction of 400 observations between 2015 and 2018 performed with TAU. Combination is performed by averaging the residuals for each wave-point. The single observed spectrum from the top plot is shown for visual comparison.