Atmospheric models of MASCARA-1b computed with petitRADTRANS with (black) and without (grey) considering the broadening produced by the tidally locked rotation and the movement of the planet in one exposure. In the top row we show the mean observed stellar spectrum (blue) and the telluric corrected spectrum (black) as reference. The light blue shadowed regions indicate those wavelengths that are not considered in the cross-correlation analysis due to telluric residuals or a low S/N.