View Full Version : OT Building an Orrery

12-12-2010, 11:17 PM
I saw a thing on TV yesterday about a ancient solar calculator that some one had found in a old ship wreck. I think it was Greek. It reminded me of a mechanical solar simulator that we had at school. That was back in the fifty's. It had the Sun and all the planets revolving around it and was driven by gears and chains.
I got to thinking it would be a good protect to build, because it would involve some gears to be made, some shafts, some bearings and could be made out of brass, wood, plastic and aluminum and any other material found around the shop.
After several hours of searching on the computer I found it to be named a "Orrery"
An ornery is a mechanical device that illustrates the relative positions and motions of the planets and moons in the solar system in a heliocentric model. They are typically driven by a clockwork mechanism with a globe representing the Sun at the center, and with a planet at the end of each of the arms.
One that caught my eye is in the following link. http://brassorrery.blogspot.com/2009/09/orrery-instructions.html

Is there anyone here on the forum that has made, or attempted to make one? If so, what are your thoughts about building one. My guess is that this thing will be very much over my capabilities, but that's makes it a good challenge.

12-12-2010, 11:21 PM
An ornery is a mechanical device

I was thinking that too.

12-12-2010, 11:22 PM
The show was probably about the antikythera mechanism. there was a thread 2 days ago about it. if you google it, you should find lots of info

12-12-2010, 11:27 PM

i just checked out the link, and he spent over $300us to buy the gears for that thing!!

I have been thinking about trying to make one for a while, but without buying cutters and thicker brass rings, i dont think i would be able to make gears that would be accurate enough.

12-12-2010, 11:28 PM
An ornery is ....

....a HSM poster in the dog days of summer?

12-12-2010, 11:31 PM
My wife often calls me orn-ree.

12-12-2010, 11:44 PM
I designed and started construction of an orrery. I cut several worm gears and worms to accomplish the needed gear ratios. I also used plastic sprockets and chain from the link below. I was planning on hiding all of that in the base, but it doesn't look too bad. I may make the base with some clear glass windows so you can see all the clock-work while you turn the handle. I also have an "earth arm" which has several brass gears I salvaged from something (don't remember what). Those gears cause the Earth to rotate about its axis and the moon to orbit the Earth.

Once I finish it, I'll post a thread on it.

12-12-2010, 11:57 PM
My lady friend and I estimate that our home planet, " Hedon" , is so far out of our solar system that no model which includes it could remain in scale. We are confident, however, that some day the mothership will return for us.

12-13-2010, 12:21 AM
When and IF I build this "ornery" Orrery:D (I think that was from MS Word's spell checker) I will use what ever material I have on hand. The gears will probably be of aluminum, I have a lot of that.
Like the builder in the link I posted says,it's Not to scale and the accuracy of the rotation and such is really not achievable for the average builder.
I'm sure not going to buy the gears when they are rather simple to make. The tubing, shafts and chain are all that I should have to buy, the rest of it, I think I have or will make.
I like Fasttrack's thoughts on the one he started.

12-13-2010, 01:31 AM
The only important component of a specific orrery is that it has to be accurate over the period of time you are employed by an omnipotent but crackpot dictator or self-described demigod. Prior or after that they can be pot metal wind up toys - doesn't matter.

Forrest Addy
12-13-2010, 01:32 AM
Funny you should mention it

Once is a great while you come across a marvelous gadget like an orrery. An orrery is a scale model of the solar system where by mechanism all the motions of the planets and their satellites can be simulated in miniature motion around the sun. Inside it’s a miracle of clockwork. It's a gadget lover's dream and a great teaching aid. When well made and imaginatively embellished one can be a work of art all by itself and beautiful examples once graced the novelty rooms of grand houses in the 19th century.

My first contact with an orrery was in 1971 when I visited my uncle Lyle in Utah. He had to show me the sights and we had a great time. We happened to be at Dead Horse Point Utah where the parking lot fronts almost on the view-point - a marvelous vista of the North end of Grand Canyon where cubic miles of empty air below our feet emphasized the immense scale of the works of nature.

The Park Service was developing a tourist attraction nearby and among the new features was a planetarium, a lecture hall, and among the exhibits there was to be a beautiful orrery the rangers could use to illustrate their evening lectures on the mysteries of planetary motion. The orrery was built by a specialist sculptor. It was a grand glittering piece of brass and porcelain enamel and fine mechanism eleven feet across which arrived in time for our visit.

I was drawn to it like a moth to a flame. Naturally we had to rubberneck.

Apparently its creator was a far better sculptor than driver. He'd un-tarped and un-lashed the magnificent piece and was backing the trailer to get to the loading door when he jack-knifed it slightly. In slow motion the orrery tipped off the trailer, rolled on its wide round base like a huge pie tin across the parking lot, gained speed on the gentle slope, bounced over the curb, and went over the guard rail to roll into the gorge. There came a fine series of diminishing crashes as it fell from terrace to terrace to terrace for thousands of feet to scatter its glittering remains on the bank of the wide Colorado River, a mere ribbon of water far, far below.

A dozen people tried to stop it and a dozen people watched it go down the canyon. When it finally came to rest there was brass and fine mechanism scattered all the way down the slope; over a year's work was ruined and unrecoverable, sparkling wreckage amid a treeless desolation. We all looked at each other and at the weeping sculptor, a tragic figure if there ever was one.

People gathered at the guard rail. There was a grieving hush such that you could hear the roar of the river nearly a mile below. A small voice spoke. "That's a long way to tip orrery."

12-13-2010, 02:04 AM
A new age version of the damage might have been "Jupiter was found in Uranus".

12-13-2010, 02:31 AM
Yea, I remember hearing about that ...
it was some kind of wind up thing wasn't it?

12-13-2010, 04:32 AM
Of course if you prefer to buy one rather than make your own (blasphemy, I know) then there's a guy in Australia (http://www.orrerymaker.com/)who will oblige.

Be sure to be sitting when you look at the prices.:)

12-13-2010, 05:26 AM
This guy has a couple of orreries to show off. He also has a rather high opinion of himself. It is however well deserved. Have a look at some of his clocks too.


Weston Bye
12-13-2010, 05:51 AM
Digital Machinist carried a series on an orrery, beginning Volume 4 Number 3.


12-13-2010, 06:38 AM
Last year I visited Eise Eisinga's Orrery in Franeker, Friesland, Holland.

He made it in 7 years, finishing in 1781, still running to this date and candidate for the world heritage list.

The display is on the ceiling of the living room, the mechanism consumes most of the first floor. It's huge.

Large gears, made of wood, with nails functioning as tooth.

Very clever solutions such as elliptical gears and excentric gears for proper display of for example moon risings.

They sell simplified diagrams with all the tooth numbers, so that work was done 230 years ago.

12-13-2010, 07:01 AM
A small voice spoke. "That's a long way to tip orrery."


That joke is wasted on this lot, Forrest

12-13-2010, 10:00 AM
My lady friend and I estimate that our home planet, " Hedon" , is so far out of our solar system that no model which includes it could remain in scale. We are confident, however, that some day the mothership will return for us.

Well, good luck to the two of you and I trust you're enjoying a VERY good time together here on our planet. ;)

12-13-2010, 10:41 AM

That joke is wasted on this lot, Forrest

Care to explain why or did you just want to insult everyone?

12-13-2010, 12:40 PM
Care to explain why or did you just want to insult everyone?
No Insult implied. :)

Forrest merely told a very funny joke that no one else seems to have 'got'. (all too young perhaps?)

(Hint: google for popular songs of the Great War)


12-13-2010, 12:49 PM
I got the joke. Forest has "told" it before.

It sort of reminds me of the joke of the new guy in prison. Every once in a while someone in a cell on the block yells out a number and the other prisoners break out in laughter. The new guy can't figure out what is going on so he asks his cell mate. The cell mate explains that they have all heard the jokes so many times before that they have just assigned them numbers to save time telling the joke. He shows a list of the jokes to the new guy and new guy decides to tell one.

He shouts "39". Silence ensues. He asks his cell mate "Why didn't anybody laugh?" The cell mate replies "You didn't tell it right".

12-13-2010, 02:51 PM
No Insult implied. :)

Forrest merely told a very funny joke that no one else seems to have 'got'. (all too young perhaps?)

(Hint: google for popular songs of the Great War)


no problem, he had told it before so that might have quelled the rush.... though your phrasing was easily taken as this group is far too loutish to appreciate the humour. Quite possibly that is the case, still, it stings to be reminding of it :)

Weston Bye
12-13-2010, 02:59 PM

That joke is wasted on this lot, Forrest

Got the joke, must have been struck dumb.

12-13-2010, 05:53 PM
Excellent story, Forrest, excellently told, and the punch line is great too.

Now, tell us, was the whole story made up just for the last line ? Or did it really happen ? We need to know. I wept with the constructor.

Forrest Addy
12-13-2010, 07:10 PM
The key to a good shaggy dog story is to sweep the audience up in the narrative and capture their symphaties - then abuse them with a hideous pun or a holpessly protracted denuement.

How better to fulfil these objectives than the a tale of the destruction of a fascinating and priceless artifact by ludicrous accident before the eyes and by the hand of its creator? What better pun than one crafted from a over-strained paring like "tip orrery" for "Tipparry" from the WW I propaganda song? If one were to be tedious and grammatical, it should have been "tip an orrery".

Good shaggy dog stories should elicit groans, ostracism, or even a trip to the Emergency Room. It's an emotional revulsion thing where the teller takes a definite risk. All the better if the listeners have to castigate themselves with "I shoulda seen it coming."

My apologies for hijacking the thread with my elderly story however it was an opportunity I couldn't resist.

12-13-2010, 07:24 PM

That joke is wasted on this lot, Forrest

I think it was about 1950, when I last heard about the Rarey and the Furry with the syringe on top.

12-13-2010, 08:44 PM
Wanna make a really fancy one? Have it do the proper elliptical orbits :)

12-13-2010, 09:23 PM
With inclination, precession and nutation. In fact, for any given body orbiting the Sun it takes over 100 periodic terms to describe the orbit reasonably well. For most purposes that can be reduced to only a dozen or so at the expense of some accuracy by averaging the smaller terms. It is impossible to fully describe an orbit as the problem of solving all the terms is utterly intractable. We do not even have an analytical solution for the orbits of just three massive bodies around each other. Note: Technically there is a solution but it coverges so slowly that it cannot be used.

12-13-2010, 09:31 PM
Wanna make a really fancy one? Have it do the proper elliptical orbits :)

I'm going to make a heliocentric Antikythera mechanism (orrery), just to be sacrilegious :D

Actually, someone beat me to the sacrilegious part. Behold, the Lego Antikythera: