Top: RV curve based on all 124 RVs of the Hα absorption and old DAO mean RVs (Plaskett & Pearce 1931). We highlight the old DAO RVs (red; decreased in RV for the difference between the systemic velocities of these, and new spectra), new DAO and Ondřejov RVs based on a sharp line core from epochs where significant circumstellar matter is present (blue), and Ondřejov and BeSS spectra, based on RVs of broad Hα profiles without perceptible emission (green). Our solution of Table 3 is shown by a solid line. Bottom: phase-locked variations of the V/R ratio of the double-peaked Hα emission. For both plots, ephemeris (1) was used.