Doppler maps and corresponding observed and reconstructed trailed spectra of the Hα, Hβ, and Si II 6347 emission lines. The position of the WD (lower cross), the centre of mass of the binary (middle cross), the Roche lobe of the secondary star (upper bubble with the cross), and the predicted trajectory of the gas stream in the form of the curve are marked. The circle shows the tidal truncation radius r_max of the accretion disc, assuming a circular Keplerian flow. The colour bars indicate normalised flux on a linear scale.