Hα transmission spectra and light curves for WASP-69 b. Top: 2D transmission spectroscopy maps in the stellar rest frame for UT 24 July 2019 (top left) and UT 09 August 2020 (top right). Dotted red lines mark the position of the Hα line in the planet rest frame. Bottom: spectroscopic light curves (bottom left) and weighted average of the full in-transit spectra in the planet rest frame (bottom right; the equivalent in the stellar rest frame is in the left panel of Fig. A.5). Light colours indicate the not binned transmission spectra, while dots represent the transmission spectra binned 20 × (in RV). We superimposed the Gaussian profile derived from the best-fit parameters on the unbinned spectra.