Section of the spectrum around sodium D1D2 lines. From top to bottom: SAO echelle spectrum, phase 0.584, Rozhen Coudé spectra, phases 0.869 and 0.291. Mesured radial velocities of primary (RVP) and secondary (RVS) are marked. The synthetic spectrum of the secondary is drawn with the proper radial velocity shift. The corresponding lines in the primary and secondary component are outlined using arrows. Dots above the echelle spectrum designate positions of telluric lines contaminating the stellar spectrum, some of them are marked with vertical bars. The spectra are shifted down by 0.2 in ordinate intensity for clarity.