Reference: The 3-D shaping of NGC 6741: a massive, fast-evolving Planetary nebula at the recombination-reionization edge
Sabbadin et al. (2005) - A&A 436, 549
The fixed image at the start of the movie corresponds to the nebula as seen
from Earth (North is up and East is left).
Each movie is about 90-150 Kby in size (avi) or 150-300 Kby (animated gif).
Rotation around the N-S axis