Upper panels: Hα line intensity and velocity profiles along the slit for two Gemini observations with PA = 125° (left-hand panel) and PA = 22°. SE–NW and NE–SW directions of the slit are shown. The solid vertical line corresponds to the position of BAT99 3a, while the dashed vertical lines (at ± 3 arcsec from the solid one) mark the area where the RV was not measured because of the effect of BAT99 3a and star 2. Bottom-left panel: He ii λ4686 line intensity profile along the slit for the second du Pont observation with PA = 90°. E–W direction of the slit is shown. The solid vertical line corresponds to the position of BAT99 3a. The solid horizontal line shows the background level and the dotted horizontal ones show ±1σ of the background noise. All data are background subtracted. Bottom-right panel: MCELS2 Hα image of the circular shell with the slit positions for the three above-mentioned observations indicated. Dashed lines correspond to the Gemini slits and the solid one to the du Pont slit. Concentric, dashed circles are overplotted on the image to make its comparison with the Hα and He ii λ4686 line intensities and Hα velocity profiles more convenient.