Geometry and conditions for CARMENES observations of HD 332231 b transit. (a) Altitude of the target at the observatory, whereby the red lines present the duration of the observations, with the cyan line representing the full exoplanetary transit. (b) S/N of the spectra calculated by the pipeline in the VIS and NIR channels, at the given specific wavelengths. (c) Retrieved water vapour column density by molecfit in mm, with the 1σ confidence shaded in light blue. In all panels the dark and light shaded regions are the astronomical night and twilight, respectively, whereby thetime axis has been broken for better presentation and midnight is in UT. Please note that no atmospheric seeing values were recorded at the observatory for the observations and the cause of the discrepancy in the S/N values of the first night observations in the VIS and NIR channels is not entirely clear.