Normalised sum over all spectra taken during night 1 around the sodium D1 line at ∼5896 Å. The normalised sum before telluric correction is shown in black, after the application of the telluric correction in dark green. The light blue dash-dotted line indicates the telluric profile generated for the spectra at transit centre for night 1. The telluric influence on the spectra was corrected down to the noise level and does not impact the transmission spectrum.