Polarization spectra of the stars showing no clear polarization change across Hα. In each case, the normal (intensity) spectrum is shown in the lower panel, the polarization (in per cent) in the middle panel, while the position angle in equatorial coordinates is plotted in the upper panel. In each case and in the following figures (unless stated otherwise) the data are rebinned such that the 1σ error in the polarization corresponds to 0.1 per cent as calculated from photon statistics.