Photometric data. Upper panel: V-filter light curve from AAVSO and KWS data, including G-filter data from Gaia. Lower panel: (V-Ic) colour together with (G_BP -G_RP) colour from Gaia. Each point corresponds to one night. The uncertainties are smaller than the data points. We note that the y-axes for Gaia data are on the right of the figure, but the scale unit sizes are the same for both V -filter and Gaia data. However, the axis limits for V filter and Gaia are different in the upper panel.