The planet Mercury has an extremely eliptical orbit about the sun. In addition, like the earth's moon, its period of rotation equals its period of revolution. It therefore presents one face to the Sun throughout its year long voyage.
This mechanism demonstrates Mercury's behaviour quite well. Although constructed for manual operation at exhibitions, fitting a motor drive should pose few problems.
There is more information about the model on page 3 of the International Meccanoman Number 8, issued January, 1993.
