Astronomical clock ideas

[Brutha]

Hi All, 

I’m thinking of making an astronomical clock - not really as a really functional object because I need it, but rather as a nice thing to have on the wall and glance at occasionally! And also as a fun electronics and maker project.

The basic idea is that it will be a 24 hour clock face with 12 midday at the top (corresponding to due south). Then there will be hands corresponding to various objects - the sun, local sidereal time, the moon and as many planets as I can cram in! So, broadly speaking if the Jupiter hand is pointing to 9am, I know it’s currently up in the south east for example.

The electronics and programming to figure out *where* the hands need to point I think I can figure out (maybe a Pi zero or similar, or could be something more basic with an internet connection).

The trick is powering the hands though. Normal stepper motors use too much power I think to be left on 24/7. So it will have to be something similar to the Lavet-type steppers used in clock mechanisms - but these are generally very low torque, and I will want 8 or 9 of them powering different hands, so the gearing will be complicated, and I’m not sure the cheap clock mechanisms you can get on eBay will have anything like the torque required (although I have ordered one and will start some experiments!). Possibly I can build my own Lavet type mechanism with coils and magnets - but not sure!

An alternative idea was to have concentric rings on bearings, with each object being one ring. But again we have the issue of driving the rings.

Does anyone have any clever ideas?

Cheers

Brutha

[Mr H in Yorkshire]

In 1410 it was done like this! Do you have a big enough wall? Sorry facetiousness only no clever ideas.

[Andy ES]

Best of luck with your project, it should be fascinating. if I ever finish decorating I would like to try something like this. 😂I I love my orrery app.

There was a very talented person, called Gina, on this forum, who is sadly no longer with us.

You could look at some of her posts maybe, as she made all sorts of clocks and 3D printed things.

[Brutha]

2 hours ago, Mr H in Yorkshire said:

In 1410 it was done like this! Do you have a big enough wall? Sorry facetiousness only no clever ideas.

Hehe, this was exactly one of the inspirations!

[Brutha]

1 hour ago, Andy ES said:

Best of luck with your project, it should be fascinating. if I ever finish decorating I would like to try something like this. 😂I I love my orrery app.

There was a very talented person, called Gina, on this forum, who is sadly no longer with us.

You could look at some of her posts maybe, as she made all sorts of clocks and 3D printed things.

Yes, I read a lot of Gina’s posts, they were always interesting, and I was very sad to hear she had passed away,

The picture you posted is very interesting - rather than just one large clock with lots of hands, probably a large clock with various small dials is the way to go - time for a ponder!

[Chriske]

We often shared files, Gina and myself
Gina's giant clock was one of here favourite projects. She printed it on here 'Giant printer'.
She sent a copy of here clock(she drew it her self..!!) to me. If I'm not mistaken it has a diameter of nearly 500mm
It used a small stepper...

[Captain Scarlet]

Why would you bother when for a mere €400,000 or so, you could get a Patek Philippe Grande Complication? 🤣

[Brutha]

On 29/10/2023 at 15:54, Chriske said:

We often shared files, Gina and myself
Gina's giant clock was one of here favourite projects. She printed it on here 'Giant printer'.
She sent a copy of here clock(she drew it her self..!!) to me. If I'm not mistaken it has a diameter of nearly 500mm
It used a small stepper...

Ah thanks for that! Yes, I am thinking of using a small stepper (maybe a 28-BYJ48, since as it has gears I can switch it off after moving it, and not use much power).

Currently I am thinking of something like the pic show - I will rotate the whole bit in the middle over the course of the day (with the notch showing local solar time), then update the hands maybe once a day.

But I haven't figured what to use to move the hands in the middle!

Cheers

[saac]

Found this offering of the Prague clock on Etsy. Looks like it is laser cut from birch ply, may give you some inspiration. 

Jim 

https://www.etsy.com/uk/listing/1594994603/prague-astronomical-wall-clock-unique?ga_order=most_relevant&ga_search_type=all&ga_view_type=gallery&ga_search_query=prague+clock&ref=sc_gallery-1-2&pro=1&frs=1&referrer_page_guid=f743a6e6641.a89e442282fdfd6ed5f4.00&plkey=9a86244c7e89e4c68bfb1e8529da184c80c3c1db%3A1594994603

[Macavity]

I did envisage a boring LCD Astro Clock. Now on "back burner"! lol
I sense you can be fairly "safe", with motions of Celestial Bodies...
It's just a "simple" matter of programming... a few equations etc. 😛

I get a feeling these (detuned?), cheap, analog clocks are not very
good - Even for predicting Lunar Phases? But you might just make
use of / upgrade(?) some attractive Clock / Dial into something? 😉 

P.S. I live close to Sea, but gave up ambitions for a "Tidal Clock".
That's an entirely different Can o' Worms?!? (+ I don't even Fish!) 😅

Edited November 5, 2023 by Macavity

[Brutha]

21 minutes ago, Macavity said:

P.S. I live close to Sea, but gave up ambitions for a "Tidal Clock".
That's an entirely different Can o' Worms?!? (+ I don't even Fish!) 😅

Hehe, I have long wanted to do something similar as I’m also close to the sea, but in the UK the government guards the harmonic constants you need very jealously (because the tides depend a lot on the local seabed shape and have to be empirically measured)…. And I didn’t figure out an easy way to reverse engineer them from the short predictions they give for free!