Correction for fiber B and telluric lines in the region of the sodium doublet. Each panel shows a respective night, with the master of raw spectra from fiber A (uncorrected for fiber B and telluric lines) in orange. In green, we show the master of fiber A spectra corrected for fiber B and telluric lines. The respective average telluric profile and fiber-B emission are shown in blue and gray, respectively. Please note that fiber B is on an arbitrary scale due to normalization. The zoomed-in image of the inset focuses on the wavelength region of 5890–5891 Å.