Left: comparison between Hα velocities derived through three different methods, with the velocities derived by the mirror method as ordinates and those derived from moments (black dots) and two-Gaussian correlation (blue stars) as abscissae. The dotted diagonal indicates equality. Right: derived velocities phased with the average ephemeris of Bjorkman et al. (2002). Symbols are black dots for the centroid derived from moments, blue stars for velocities derived from the two-Gaussian correlation, and red crosses for velocities derived by the mirror method. The dotted cyan line provides the orbital solution of Bjorkman et al. (2002).