Novian Orrery Project (The Returnening!)

Oct 13th and 14th is Amazon Prime day. I bought my 3D printer three years ago on Prime day, after several years of waiting for the right price. If there is a better time to buy a 3D printer other than Prime Day, I've not found it.

Lots of YouTube on 3D printed gear strength. I print in PLA primarily. PLA is strong but I suspect the torque on your proposed project would strip all but steel gears.
Recommended video: https://www.instructables.com/8-Planet-Motorized-Orrery-3D-Printed/

 

Well, they make these in brass (weaker than steel) far more complex than mine is/will be. I will likely have to use some press-in bearings to keep friction down, but will probably do one or two planetary trains first to get a feel for what I'm dealing with.

 

Only one way to know for sure.

 

True.

And if it's a bust, I'll at least have most of the design work done so that if I ever go back to being a machinist (or can afford to acquire all the tooling myself) I'm all set to make a proper brass and steel version.

 

New snag: The sun on an orrery rotates. More specifically, the shaft it is mounted to rotates. New Brittania does not. Not entirely sure how to solve this one.

One solution is cannon pinions. Essentially, a gear with a tube. If you have a stack of gears, the bottom gear would have a tall thin tube in the center. The next gear in the stack has a shorter tube, which is wide enough to fit around the first tube. The third has a tube shorter and wider than the second, and so on. End result is a stack of gears that all spin independently, and a series of nested shafts. Put a bracket that holds each planet on the exposed end of each tube, and you have a series of planets that can all spin around the same center axis. If I put that entire stack of cannon pinions on a fixed shaft, I could put NB on the end of that fixed shaft.

Problems though, are many. To make the tubes strong enough, I'd have to print them probably with 2mm wall thickness, probably more for the larger ones. If the internal diameter if the first one is 4mm, that's 8mm (2+4+2) total diameter. Each successive tube adds 4mm. With 10 satellites, that's 44mm, which is pretty big. Bigger than some of the gears, unless I scale the whole thing up a lot. Also, in 3d printed material, that's going to be a lot of friction. I could use brass tubes pressed into the gears, which would let me get away with much thinner tubes. But that'll get expensive, since I don't currently have access to the equipment to make them myself. If I buy them, it's also wasteful, as the biggest diameters (and so most expensive) are the shortest pieces, but I'll likely gave to buy stock lengths, probably around 300mm at least.

Quite the puzzle.

 

I've been looking through programs such as this https://www.nbos.com/products/astrosynthesis .
I believe the demands that are needed to make something like this useful, is an easily accessible way to be able to not only create an orrery the same as New Britannia, but even more importantly, it must have the ability to be moved both forward and backward in time to predict events in the future, yet also study past events for "discovery of hidden planetary effects of our sky that influence our game".

Currently, if there were (for instance) planets effecting agriculture, we would have no way, (other than wasting allot of time noting planet/moon positions at time of harvest, which would be statistically happenchance at best with false positives and negatives abound.

"Unless our program's developers actually told us for fact, providing specific details about planetary effects, then it would be forever impossibly unlikely such an effect would ever be detectable, predicable or noted through observations".

My search for deeper SOTA through our astrology continues, deeper Ultima fail, deeper game fail...

The above mentioned software demands that any "built fictional system" obey actual laws of physics, which New Britannia's sky does not.

I wish you the best of luck in this, your most important current orrery project @Cora Cuz'avich !
No Tardis no fun! ~Time Lord~

 

A few ideas.

Specced out the cost of telescoping brass tubing. It's not as bad as I thought it would be. But there is one additional wrinkle to this arrangement- the gears are essentially all in one long chain, each being driven by the previous, from beginning to end. This might work well with metal gears and tight tolerances, but it's not ideal for printed parts, given that it's around 50ish gears in all. Plus, the math for the gear ratios gets insane, since each planet's period affects the calculations for the next, all the way down. My original design has a central steel keyed drive shaft driving each planet's gear train individually. At most, there's no more than six gears in a chain, and each train's ratio is calculated from a single input.

Another idea is a hollow keyed shaft rotating around a fixed shaft. Biggest issue there is I can't find keyed hollow shafting. I might be able to make it myself if I can find aluminum tubing with thick walls and a narrow enough outside diameter. I could build a jig to hold it and run it through my table saw to cut the keyway.

Decisions, decisions.

 

3D Printer should be delivered on Thursday!

 

Spoke Posted too soon on that one. Looks like the nozzle clogged prior to the last few layers. Also, the text was probably not going to come out very well. I have some ideas show to fix that, but I'll probably try a smaller gear next time; that was a three hour print. Though, I may just have to abandon the idea of having fancy "engraved" gears. This is what I was going for:

 

Ordered a smaller nozzle (originally didn't think they had smaller ones for this type of extruder, but I must have had a dumb search term when looking for them). Have some other ideas how to improve the text. Oddly, making it narrower might help- since the text is made by printing around them, the negative space is less important to the crispness than how much space is between the characters. Plus some slicing tricks.

Worst case, I just don't have pretty fancy gears. But The ring that shows the consteallations/seasons/months is going to need text, so I need to figure this out. I suppose I could always print the ring with slots to fit inserts with the text, then print the text bits on my SLA printer. I'd have to paint them, though, so they likely won't look like the printed ring.

 

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Looks like @Lord British is working on some similar projects.

@Cora Cuz'avich, Could any ideas from the Lego Antikythera be useful to your Orrery Project?

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https://twitter.com/DoktorCat/status/1333076764575354884
Dr. Cat - Jubilant
@DoktorCat
Here's another thing @RichardGarriott could survive without, but ought to have anyway because he could appreciate it better than almost anyone else:
8:54 AM · Nov 29, 2020·Twitter Web App



Lego Antikythera Mechanism
Dec 9, 2010

The Antikythera Mechanism: http://bit.ly/fm4oFK is the oldest known scientific computer, built in Greece at around 100 BCE. Lost for 2000 years, it was recovered from a shipwreck in 1901. But not until a century later was its purpose understood: an astronomical clock that determines the positions of celestial bodies with extraordinary precision. In 2010, we built a fully-functional replica out of Lego. Sponsored by Digital Science: http://www.digital-science.com/ a new division of Macmillan Publishers that provides technology solutions for researchers. Available under a CC-BY-3.0-Unported license.

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https://twitter.com/RichardGarriott/status/1333140654034137095
Richard Garriott
@RichardGarriott
Way ahead of ya! My unlucky buddy Mike is building one. We are also building orrery and automata together!
1:07 PM · Nov 29, 2020 from Manhattan, NY·Twitter for iPhone

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Not really. Though, I did find Clickspring's youtube videos on constructing an accurate replica to be helpful. I have a rough idea of the overall design, and I have all the gear ratios worked out. I've just been too busy with other things the last two months. Fortunately, since SotA astrology is invented and not "natural" it's not nearly as complex as something that's trying to model the real world with eccentric orbits and all that.

I got my smaller nozzle, so maybe this weekend I'll take another crack at printing a gear. This time I'll try and make the smallest gear I need. Not only will it not be an all day print, but it'll give me an idea as to whether or not I need to go bigger on things to get them to work. (Or, it'll let me know if I can go any smaller, which would make things easier.) Once I know how small I can make the gears, I can design things in earnest.

 

I don't know if anyone has mentioned this but if you place your moondial in a basement, you can observe the movements in a much accelerated rate. This might help you grok out the ratios.

 

Is that some sort of bug? Or is it just no longer tied to the actual astronomy if it's placed indoors, and just runs on it's own time?

Either way, Bowen worked out all the orbital periods a long time ago. But that could still come in handy.

 

It's not a bug. There's no skybox in basement scenes for it to sync against, so it just turns at an accelerated rate. It's actually pretty cool.

 

Interesting. I would have thought the mechanics of the astronomy were always running in the background, and the moon dials were tied directly to it rather than the skybox. Though, I suppose it's easier to to only make the calculations for positions once for the skybox, and then use them for all other items that need the data. Especially if you were in a PoT with like, a hundred moondials or something.

 

Ooo, there's a decorating idea.

 

Well, then.

So, "thanks" to Alley Oop, I now know that half the constellations are above the ecliptic plane, and half are below it. Additionally, the planets are all actually above it. (Or maybe below it. Novia being in the southern hemisphere and me living in the northern hemisphere makes things a little confusing sometimes.)

The issue at hand is, how this affects sieges. As it seems to be that the planets will only cross constellations on the same side of the ecliptic plane as they are. Which would mean half the constellations don't trigger sieges. If they trigger them only when they are in the same segment of the sky as the constellation (but not directly in front of it) then fine. But why are they offset? A theory is that they only trigger sieges in PoTs if they are directly in front of them, but work in the same segment of the sky for NPC towns. But then, we're back to half the constellations not triggering sieges in PoTs. But, if that wasn't the case, any PoT with all the devotionals would just about always be under siege. Another theory is that the constellations can move back and forth above or below the ecliptic plane. Maybe?

So, either way, something else is at work here. I need to collect more data.

[EDIT: The above/below the line thing is just aesthetic. As for POT sieges, it's explained in the link in the following post.]

 

Droppin' this here so I don't lose it.

https://www.shroudoftheavatar.com/f...-are-not-working-correctly.94277/#post-842412