Calibration curves of the par_stretching parameter depending on the CCF FWHM value derived for a given spectrum. The calibration was established based on nine stars (see Table B.1) that probe the spectral type range from F6 to K5 (each star is indicated with a different colour). The square dots indicate the minimum and maximum values for the par_stretching parameter (chosen by eye). The circles are more conservative (16% and 84% of the parameter range). We fit the latter on a line to derive the minimum value in automatic mode (par_stretching = “auto_0.0”, dotted) and the maximum of the parameter (par_stretching = “auto_1.0”, dash-dotted) as a function of the FWHM. The final choice is then at the user’s discretion. The nearly constant line shows the minimum value, and the decreasing line shows the maximum value.