Spectra of χ Cyg on September 4, 2007. Left: around the region of the Na D doublet; right: around a Ti I line in the near-infrared spectrum. The thin black line shows the intensity (ordinate axis on the right) in normalised units, whereas the thick coloured lines (blue for U, red for Q) show the linear polarisation spectra. The rest wavelength of both Na D₁ and D₂ in the left plot and the Ti I line in the right plot are represented with a vertical dashed line.