Data-processing steps for a single echelle order. Top: raw extracted time-series spectra after cleaning of outliers. Middle: time-series spectra after blaze-correction. Bottom: detrended residuals from the division of the SYSREM model weighted by the uncertainties. Minor structure remains in the residuals due to lower weighting of low-S/N orders caused by poorer seeing (horizontal banding) and due to imperfect removal of time-dependent tellurics (vertical banding at bottom). The telluric structure does not persist into the in-transit frames and is therefore weighted-out in later analysis.