The Bad Toelz Planetarium

Posted by: albert Mar 22 2021, 03:08 AM
QUOTE(Ron Walker @ Mar 21 2021, 11:55 PM) *
I would imagine the Annual motion motor is inside the central core.

the motors are too big to fit inside the core- remember this is a miniature machine- the whole dumbbell is only 3 feet long. Only precession and hour circle motors are inside the core.

The planet gears are interesting. Since there is no planet cage the gears are strung on the center post like on a barbecue. Therefore nothing can go across the center but everything has to revolve around the post. Much closer to the Antikythera machine than anything else. Have you seen the latest reconstruction? Mind blowing.

vimeo.com/518734183

I hope I can post pictures here soon- have no program to down convert the images I shot during the montage.

Albert

That is quite the video. The ancients knew much more then they are given credit for. I often look at the statue of Atlas holding the Earth on his shoulders and standing on a turtle. A turtle is slow so does this represent the driving force for the processional motion of the Earth.

I look forward to detailed pictures of the planet projectors and how everything is run off of the central post. A most interesting design.

Posted by: albert Mar 23 2021, 08:33 AM
QUOTE(Ron Walker @ Mar 22 2021, 06:27 PM) *
Should work like this:

Choose File should open access to your computer. From the files there choose a picture and open it. It should appear right after Choose File. Then press the green box UPLOAD. After a bit it will appear under Attachments to the far left. You will see "Manage Current Attachments (1) and press the down arrow and find your picture. Press the first box with the green + and your picture should come up where your curser is located.



If the image is overly large, the site will reduce the size and ask if the viewer wants to see it in full size. I usually reduce the size to a 600 pixel width so I can upload several pictures in one post. If you like, you can email me the pictures and I will reduce them and either post them or send them back to you for you to post. I would probably want to view the full image anyway to get a true understanding as to how the gearing works.



After adjustment.


thank you- last time I tried, the first step didn't work- let's see- great, here are some of the motors. Precession is top right, the one in the center is the diurnal motor.

Posted by: albert Mar 23 2021, 08:55 AM
QUOTE(albert @ Mar 23 2021, 04:37 PM) *
This is a closeup of the moon projector. The slot in the middle rotates very slowly to simulate the moon nodes moving across the ecliptic- (metonic cycle, I believe...) there is only one gear coming from the center of the machine driving the whole stack.



this is the mercury projector- above the Moon projector.Here we have a tilted disc and a crank mechanism- much like a windshield wiper. The tilt od the disc corresponds to the tilt of mercury's trajectory- so this creates right ascension and declination of the Mercury projector at once- The whole thing rotates on a plate that has the Sun, Gegenschein & Year Counter mounted on it. The Sun projector is seen above. So it keeps Mercury and Venus in sync with the Sun. The little tube at the side of the projector is a mercury switch (no pun intended) for turning off the light below the horizon. All the gears suppose circular planet trajectories- no simulation of eccentricities in this machine.

Posted by: albert Mar 23 2021, 09:28 AM
QUOTE(albert @ Mar 23 2021, 05:21 PM) *
This is the lower stack of the projectors (South star ball)- Mars, Jupiter, Saturn. Here they use discs without tilt and do the declination with small excenters on which ball bearings are mounted. These push the mount of the projector up and down. If one loosens the 3 large screws on top of the larger gears, one can rotate these gears for setup purposes.




This is the saturn crank-not tilted.



And this is the small eccentric piece with the ball bearing for the declination of the planet. Pretty clever idea, I think.



I cannot claim to have understood all the subtleties of these mechanisms yet. But they are very clever and give the projector its small footprint.

That is it for today... Ron, I hope you have not been eaten by the "face hugger" yet and these pictures do not come too late!

My goodness how long since I last posted pictures here??

Posted by: albert Mar 23 2021, 03:37 PM
QUOTE(Ron Walker @ Mar 23 2021, 09:02 PM) *
So Mercury and Venus are on the same plate between the Moon and Sun. That is a very unique design. Then the center post of each does not move (except perhaps during precession)? Then is there a second center post that rides around the inside fixed one?

I think there are two coaxial tubes. The inner one rotates the star balls for precession. The outer one is fixed and the various stages rotate on large ball bearings. At different speeds.

Here is a time lapse video of both South and North planet mechanisms. On the moon projector one can see the slot counter rotating - that one must be a third short tube riding on top of the others. So its really a nested design. There are gears above the tilted discs for Venus and Mercury that I have not understood yet. Perhaps they rotate the tilt to simulate the rotation of the trajectories- I'm not sure.

drive.google.com/file/d/1lsAsoJ-r6KWfgyUgjW6aVkiVcQXpIzXL/view?usp=sharing

Have you seen the new reconstruction of the Antikythera mechanism? It is mind blowing.And the basic concept is extremely similar to the gears on the projector.

vimeo.com/518734183

Would love to hear what you think of all this.

Albert

Tomorrow I will try to find a gearing schematic of the machine.