Reference: 3-D ionization structure (in stereoscopic view) of planetary nebulae: the case of NGC 1501.
Ragazzoni et al. - A&A 369, 1088 (2001)
We present a single movie (501 Kby) showing the opaque reconstruction of the main nebula (Ne > 900 cm-3 for a filling factor =1), first for a rotation around the N-S axis and then for a rotation around the E-W axis. The fixed image at the beginning of the movie corresponds to the nebula as seen from Earth (North is up and East is to the left).
N1501comp_NS_EW avi gif