Time-averaged spectra before and after the telluric lines removal. Left panels: averaged spectrum for each investigated night in the telluric rest frame, with the position of the H₂O telluric transmission line at ~1083.51 nm and the OH telluric emission line at ~1083.43 nm overplotted in black and orange, respectively. Right panels: averaged spectrum for each investigated night after the telluric removal and the shift in the stellar rest frame. Vertical blue lines correspond to the He I triplet. The averaged spectra are plotted after being divided by their median value for visualisation purposes.