Comparison between the RASSINE normalisation and the normalisation obtained with a classical approach (linear fit between pseudo-continuum windows on either side of the selected line, set text) for two broad absorption lines for three stars with different spectral types: K5V, G2V, and F7V, from left to right: 61 Cyg A, the Sun, and HD142, respectively. Top: spectral region corresponding to the sodium doublet NaD. Bottom: spectral region corresponding to H_α. Both 61 Cyg A and HD142 were normalised in automatic mode with intermediate tension (par_stretching = “auto_0.5”) and polynomial mapping ν = 1. For the Sun, a higher tension (par_stretching = “auto_0.0”) and smaller polynomial mapping (ν = 0.7) were needed to exclude the interline region of the sodium doublet from being part of the continuum. A comparison with the IAG solar atlas (Reiners et al. 2016) degraded at the HARPS resolution R ∼ 115 000 is also displayed. The deeper lines in the IAG atlas are tellurics.