`The Orrery is a ten foot tall planet tracking display. The lower half is a mechanical binary calculation engine. Each layer is calculating the orbit if one of the six human eye visible planets (Mercury through Saturn) to 28 bits of accuracy. The Orrery is primarily made of monel (a nickel copper alloy), and stainless steel. The planet spheres are ground from natural stones that resemble each planet they represent.’
Pictures of the Orrery clock also.