Time evolution of calibrated U​BV photometry from stations 1, 20, and 30 (black), and Hα spectrophotometry (V/R and I_c) over a limited time interval RJD 51500 to 59500, which is covered by electronic spectra. Data from the higher-resolution Elodie, Feros, and DAO are shown by blue circles, those from OND by the red circles, those from the BeSS amateur spectra by the green circles, those from the Trieste spectra re-reduced by us by magenta circles.