Direct images of the main nebula. First row: He ii (λ4686 Å) and [O iii] (λ5007 Å); second row: VLA (20 cm) and H α (λ6563 Å) +[N ii] (λ6548 Å+λ6584 Å) (same orientation as shown in Fig. 1− N is up, E is left). The ellipses are derived from the images of the He ii line. While the He ii emission is clearly concentrated towards the inner edge of the main nebula, the [O iii] and VLA images have about the same appearance.