Differences between ThAr laboratory wavelengths and LFC-calibrated measurements summarized by spectral order. Since the formal uncertainties of the individual ThAr lines are small (indicated in Fig. 13), the vertical error bars represent the scatter within each order. Colors indicate different fibers and slices (similar to e.g., Fig. 10) and points are slightly displaced in wavelength direction for clarity. Indicated with horizontal lines are the 16th, 50th, and 84th percentiles of all ThAr wavelength measurements.