Normalisation of the SOPHIE spectrum taken at BJD 2454828.69749. Top: the pipeline-reduced individual spectral orders (black) and the best-fitting scaled blaze functions (red) defined in Eqs. (1) and (2). Middle: our normalised and merged spectrum (black) compared with the normalised one-dimensional spectrum from the SOPHIE pipeline (orange). Bottom: the difference between the two normalised spectra shown in the middle panel. The residual instrumental trends from the one-dimensional pipeline-reduced spectrum dominate.