RV measurements based on UVES spectra taken on different nights. The first of the six spectra of our observing campaign was taken on observation night 0. The time interval in days between different observation nights is written at the bottom of the subplots. For SMC AB1, 2, and 4, we also show measurements based on the preexisting UVES spectra of Marchenko et al. (2007) (they are the data from observation nights −2 and −1). In this work we opted to use the N V lines, which are shown with thicker lines.