a Grand Planetarium on my Ceiling

This planetarium gets planet positions from NASA daily at midnight and aligns them without complex gears. A motor rotates Mercury, triggering a chain reaction among the other planets. This slow process is shown as a 30x timelapse in the video, taking 1.5 hours in real-time. The Sun houses the motor and other components, and the planetarium's diameter is 2.1 meters. There are also extra gears for the Moon's rotation.
You can make your own mini planet spinner at www.instructables.com/Grand-P...
music: "exit the Premises" Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 4.0 License
creativecommons.org/licenses/b...

[@zwmm]

Nice project. A good tribute to pre-digital days

[@tzkelley]

I love this project! But at the risk of making a comment about something I know nothing about, isn't the math to figure out the planet positions relatively straightforward? I can't imagine the angular velocity has changed appreciably over the course of 20,000 years. Seems like the connection to NASA is a source of frustration over time so maybe get rid of that dependency? Thanks for sharing this! I'll definitely be making one of these! One other question though--could you explain the function of earth's moon more?

[@illusionmanager]

relatively straightforward indeed...for range of years. The moon is a bit more complicated. Getting data directly from NASA sounds cool anyway.

[@greggv8]

That's a nice project. Could add orbit eccentricity with telescoping rods and cams in the hub. :)

[@illusionmanager]

Clever idea, but only useful if the relative distance to the sun would be correct as well. Currently it only shows the direction, which is still accurate, even when not taking into account the eccentricity.

[@AuxiliaryPanther]

Brilliant! Welcome from hackaday.

[@tzkelley]

Will you be adding the Zodiac symbols above it?

[@illusionmanager]

I'm thinking about it, but don't have the right idea that would look good. Any suggestions?

[@tzkelley]

@@illusionmanager laser cut each section and cover in gold leaf?

[@sdspivey]

Why not have Neptune fixed in place. It moves less than 0.006 degrees per Earth day, or about 2 degrees per earth year, so isn't ever going to be noticed. Less wear on the whole system and half the time as a bonus. Just rotate the entire solar system to match the Neptune location. As it stands, you should paint a calendar on the ceiling, or at least mark out the seasons.

[@illusionmanager]

because the esp32 microcontroller in the sun also acts as a webserver, which allows me to set it to any date between 9999 BC and 9999AD. Neptune moves a lot in that time. The Zero position (equinox) is currently parallel to one of the walls in my house. But yeah, it is missing a zodiac, I just don't know yet how to keep that beautiful and minimalistic. Who knows.

[@sdspivey]

@@illusionmanager I thought it only showed the current state, not that you could change it.