Hα transmission spectra and light curves for GJ-3470b. Top: 2D transmission spectroscopy maps in the stellar rest frame for transit 3, transit 4, and transit 5 in panels a, b, and c, respectively. Dotted red lines mark the position of the Hα line in the planet rest frame. Bottom: spectroscopic light curves (panel d) and weighted average of the full in-transit spectra in the planet rest frame (panel e, the equivalent in the stellar rest frame is in the left panel of Fig. A.5).