White-color light curves of GJ 3470 obtained with GTC/OSIRIS on January 30 (Run 1; left panel), February 9 (Run 2; middle panel), and March 10 (Run 3; right panel) in 2016. In each panel, from top to bottom are: (1) raw flux time series of the target (black line) and reference (red line) stars; (2) raw light curve (target-to-reference flux ratio; black points) and the best-fitting combined model (red line); (3) corrected light curve after removing the best-fitting systematics model, overplotted with the best-fitting transit model; (4) best-fitting light-curve residuals.