Left panels: Summary of time series (left panels) derived with the procedure described in Sect. 3.4 in the middle of selected features among those identified in Figs 4, 5, and 6 and listed in Table 3. In the case of the 13 April 2023 observations, the time series obtained from dataset #4 (session no. 310304) are in shown in blue. Right panels: Corresponding power spectra for each dataset shown with the same colour coding. The Lomb normalised periodograms for the full time series are drawn with red lines. The power spectra and periodograms are normalised to their respective maximum values.