Ratio of the S/N derived from the observed data by the X-shooter pipeline and the S/N predicted by the ETC for the actual observing conditions, at both blaze wavelengths of each order. The black lines show the results for the NIR data from P110 (slit width 5′′), while the red lines show the results for P112 (slit width 1.2′′). The blaze wavelengths 1376 nm and 1867 nm are strongly affected by telluric absorption, and the region around 1634 nm has strong sky emission lines.