The lego one is actually pretty nice, and cheaper than most ready-made models. The one part that isn't quite right, and I'm not even sure I've ever seen a mode

The lego one is actually pretty nice, and cheaper than most ready-made models. The one part that isn't quite right, and I'm not even sure I've ever seen a model that does this right, is the moon's orbital tilt, so the earth isn't blocking the moon for full moon, and the moon isn't blocking the sun for new moon. The distances probably don't scale to make it practical, the tilt would have to be extremely exaggerated. The phases of the moon is the only thing that I've never seen an orrery show very well.