NOT/ALFOSC transmission spectrum of WASP-127b, using bins 20 nm wide in wavelength. Error bars are ± 1σ errors. The left panel shows the transmission spectra with (black) or without (blue) the second-order correction in the stellar spectra. The right panel shows two 0.1 × solar atmospheric models computed using Exo-Transmit (Kempton et al. 2017, red model: with TiO/VO, but without Na/K, 5× Rayleigh scattering, sky-blue model: with Na/K, but without TiO/VO, clear), and a pure Rayleigh slope, together with the corrected transmission spectrum.