BOOTES-6 and BOOTES-7 optical light curves of EP240309a from 2024 March 21 to 25. Each panel shows one night of differential photometry, with time measured from the start of that night’s observations on the horizontal axis and magnitude on the vertical axis. The corresponding reference time t₀ (i.e., t = 0) is indicated in each panel in UTC. Blue points indicate individual measurements and red bars show the total photometric uncertainty (Section 2). All nights display pronounced variability on minute-to-minute timescales on top of modest night-to-night changes in mean brightness.

(The data used to create this figure are available in the online article.)

(The data used to create this figure are available.)