See:
https://arstechnica.com/science/2021...era-mechanism/

"The 82 surviving fragments of the device were originally housed in a wooden box roughly the size of a shoebox, with dials on the outside, containing a complex assembly of gear wheels within. The largest piece is known as Fragment A, which has bearings, pillars, and a block. Another piece, Fragment D, has a disk, a 63-tooth gear, and plate. The mechanism's very existence offers strong evidence that such technology existed as early as 150-100 BC, but the knowledge was subsequently lost. Similar machines with equivalent complexity didn't appear again until the 18th century. While it was found on a Roman cargo ship, historians believe it is Greek in origin, possibly from the island of Rhodes, which was known for impressive displays of mechanical engineering."

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A reconstruction of the device based on the high-resolution X-ray tomography conducted by the study confirmed it was an astronomical computer used to predict the positions of heavenly bodies in the sky. It's likely that the Antikythera mechanism once had 37 gears, of which 30 survive, and its front face had graduations showing the solar cycle and the zodiac, along with pointers to indicate the positions of the sun and moon."

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After considerable struggle, we managed to match the evidence in Fragments A and D to a mechanism for Venus, which exactly models its 462-year planetary period relation, with the 63-tooth gear playing a crucial role," said co-author David Higgon. This enabled the team to derive the cycles of the other planets as well and to create mechanisms to calculate the astronomical cycles while minimizing the number of gears so that everything would fit into the tight space of the device. The team also suggests there may have been a double-ended pointer to predict eclipses, which they have dubbed a "Dragon Hand."There are still plenty of mysteries surrounding the Antikythera mechanism, however, such as whether this latest version could really have been built using ancient manufacturing techniques. “The concentric tubes at the core of the planetarium [that carried the astronomical outputs] are where my faith in Greek tech falters, and where the model might also falter,” Wojcik told the Guardian. “Lathes would be the way today, but we can’t assume they had those for metal.”
"This is a key theoretical advance on how the cosmos was constructed in the Mechanism," said Wojcik. "Now we must prove its feasibility by making it with ancient techniques."