Steven Jones, This movie doesn't make sense, unless you tell us the vantage point of your animation. Regards, Regner Trampedach - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Quoting Steven Jones <steven@xxxxxxxxxxxxxxxxxxxx>: > Hi Paul, > > Attached is a movie file which will help you appreciate the "wobble". It > illustrates the Earth going about a year round the sun, but each frame > is a sidereal day (23h 56m). You will see that the north pole is always > changing direction so as to compensate and keep polaris the centre, > hence the wobble. > > Steven. >