Orrery's.

[planet1774]

Does anyone know who first constructed an Orrery of the solar system, and where I could find drawings or blueprints of construction?

[dundurn]

There have been several different sorts of orrery built over the years - -the earliest by the Greeks BC. The "modern" type of orrery where (relatively) to scale planets circle the Sun at appropriate speeds dates from around 1700. The second copy of the mechanism was given to the (Irish) Earl of Orrery and his name attached to the device, though he had nothing to do with its creation.

There is a part-work currently/ soon-to-be in publication which permits you to make one for yourself (no doubt at exorbitant cost). I would imagine the principal problem in making one with any degree of accuracy is in finding or making gear wheels of appropriate sizes since they are probably of little use for any other purpose. It might be possible to create a train of standard size wheels that multiply up to the necessary values, but as to where you could find a plan I can only suggest googling.

[planet1774]

Thanks for that.The name is rather interesting, as I was wondering of its origin. I saw the tv ad for the publication you refer to, which sparked the intrigue once again. I would very much like to build an accurate as possible mechanism, and would fabricate each part, if necssary.

Google wasn't particularly helpful on my first trip, but I will endeavour. As accurate (ish) drawing's or a blueprint, if such a thing exists, would solve this problem. And be the gateway to many more. Haha

[Mike S]

The gear ratios required for an Orrery are not all that complex.
I've work out a set of gears that give orbital accuracies in the order of 2.5% max. Each gear train uses 4 gears in 2 sizes so that each train has the same centre distance.
I can E'mail you a spread sheet of the ratios if you require.