Combined out-of-transit observations around the He I triplet lines for the first (top panel) and second (bottom panel) nights in the stellar rest frame. The observed stellar spectrum (fibre A) is shown in black and the telluric-absorption-corrected spectrum in blue (first night) and green (second night). The sky spectrum (fibre B) is presented inred, and the best fit profile in yellow dots. In light grey we indicate the regions that were masked due to telluric contamination (see details in Sect. 4.1.2), and the vertical blue-dashed lines mark the positions of the He I triplet lines.