a potted history of the orrery

Gilkerson's orrery - circa early 1800's

Apart from being a gorgeously wonky word, I am extremely pleased to have figured out what an orrery is. I'm currently poking around into the history of astronomy and planetariums in particular, cooking up a few ideas for projects. I sortof stumbled across this orrery word and have now become endeared to it on all levels, the most prominent of which being because it is the correct name for Aughra's observatory thing in The Dark Crystal. A film I was mighty attached to as a child and still recall an embarrassingly large amount about. Apart from, I recently discovered, the correct name for Aughra's place.

Aughra's orrery in her chrysalis on the hilltop - prior to being smashed up by the baddies

An orrery is essentially an anatomically correct physical model of the solar system. Sun in the centre, celestial bodies whirling around it, with their satellites and moons whirling around them. Anatomically correct unless you include scale, of course - that little detail being rather a hinderance as everything is so incredibly far away from each other. Scale is also not strictly observed, it seems, when it comes to the relative size of planets to each other. But every other detail is meant to be correct, in order to facilitate old men in long beards to ponder on the universe in times past, when the orrery was the prime instrument for figuring out various planetary things.

There are orrerys that just focus on the earth and its relationship to the sun and moon, with the other two closer planets to the sun thrown in for luck at reduced sizes. An incredibly cool device for actually seeing how the earth's shadow relates to the moon from the comfort of one's oak desk. I am tickled by some of the orrerys I found just for their endearing clunky-ness... their little brass cogs and planets on wires, standing up straight and true, ready to be observed, pondered, and mastered by the might of man.

What has made the most impression on me so far, though, is how achingly human these constructions seem - both in complexity and scale - a burnished example of our species struggling to understand the universe...

On a less cloying note, it would appear from the research I've done that the Antikythera mechanism was, infact, an orrery of sorts. Previously I thought it was some sortof funky navigational system which simply figured out longitude. And the crew at the Long Now have an orrery, as well as their 10,000 year clock.

the sun tile at the center of Armagh Observatory's human orrery

Apparently it is common for the terms planetarium and orrery to get mixed - usually with the orrery being labelled a planetarium, which apparently it is not, due to its physical characteristics and the fact that its bits move. A planetarium is, officially, a theatre or room where heavenly bodies are displayed as either points of light or, earlier on, as painted stars. This display of the heavens may move by rotating the lights or whatever, but it is essentially an educational tool, rather than something that you actively use to predict stuff. I think this is the story. I wish I knew a planetarian to confirm this.

I had some vague plan to construct a series of little orrerys out of cardboard and balsa wood and attach them to walls or streets, powering them by a reliably dripping drain in a laneway somewheres, but methinks the level of tactility required to construct such a thing may well be beyond me. I think at this stage I will re-focus on more planetarium-esque concepts.

Lastly, some of the orrerys that i found: Gilkerson's, The Armagh Observatory's human orrery, the Long Now's orrery, David Rittenhouse's, Eise Ensigna's, and some non-attributed photos of orrerys 1 + 2.

a miscellaneous orrery found on flickr