Purple line observation in Skibotn on March 7, 2019. We observe at a fixed elevation of 45°, and rotate the instrument (fixed on the observatory dome) clockwise starting North, following the same almucantar. Each passage to the North is marked by a vertical red line, and the direction of Skibotn is indicated by the dotted vertical line. In black are the raw data along with the associated error bars in grey, and in blue the smoothed data over 15 s. From top to bottom: the observed intensity (in mV), the DoLP (in %) and the AoLP (in degrees). We also show, superimposed with the AoLP, the apparent angle of the magnetic field lines (cyan) and the expected AoLP for scattered light for a artificial source point in Skibotn (pink).