Spectra of the BF Vel Na I D doublet at orbital phases (ϕ) around quadrature; R = 7000. Downward arrows mark the calculated positions of the line centres for the primary star (S1) and secondary (S2) that give the best fit to the RAVESPAN analyses. Lines of the tertiary component are indicated with magenta arrows angled up. Exposure times: (a) 300 s; (b) 180 s; (c) 300 s; (d) 105 s.