Illustration of lpv of Hα (left panel) and He I λ 5876 (right panel) lines in our TIGRE/HEROS spectra of HD 192639. The date of the observation is given on the right of each panel in the HJD-2450000 format. For nights with more than one observation, the various spectra are overplotted and the date corresponds to the mean time at mid exposure of all the spectra taken that night. The spectra displayed in orange-red and green-blue colours were taken during the trough seen in the TESS light curve of Sector 41.