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SocksOnHands t1_ixcknwt wrote

Reply to comment by Der_Missionar in TIL the Passemant astronomical clock in Versailles has shown the correct date, time, moon phase, planetary alignment, etc (accounting for leap years ) from 1750 and can display through 9999. by kitkatbloo

Amazing it's so accurate if it is as bad as this quote makes it seem to be.

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Der_Missionar t1_ixcly0b wrote

The clock is extraordinary... It does not say it will be accurate till 9999, rather, it says the date can "show" to 9999.... It does show "Approximate" moon phase, planetary positions, and accounts for leap years.

The glass globe that crowns the clock houses the planetary system as seen by Copernicus. We can see the planets’ orbit around the sun – Mercury, Venus, Earth, Moon, Mars, Jupiter, Saturn – their relative positions in the zodiac, and the Moon’s orbit around the Earth. It indicates the two equinoxes, the two solstices and the solar and lunar eclipses, also the solar second.

By all accounts extraordinary... I would like to see something on it's accuracy - as that is the one thing we are not told - and is to what the post title seems to refer.

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SocksOnHands t1_ixcmzpu wrote

What I meant was that the title says it has accurately shown the time since 1750, but this quote mentions grime, dust, wear, etc. It's amazing that friction or damages hadn't make the clock become less accurate over time. Was it that it was set in 1750 and is still correct today, or had the clock ever needed to be adjusted to correct the time?

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Der_Missionar t1_ixcnejm wrote

>Was it that it was set in 1750 and is still correct today, or had the clock ever needed to be adjusted to correct the time?

This is exactly what I'm referring to... NOWHERE in the articles I've seen mention how accurate the clock is. I don't know a single mechanical clock that's ever been made that doesn't need to be adjusted from time to time. The post title leaves you thinking, this clock is accurate till 9999... and it's never been adjusted... that's not what this says at all.

Clocks of the day (1700's) often kept time to 1 second per day, and new mechanisms were coming out that could keep time to 1 second per month... John Harrison proposed a time-piece that could keep time to an astonishing 1 second per 100 days... His design, however, was never finished... until someone tried it out in 2009, and finished in 2012... proving you COULD keep time with his design, in a purely mechanical clock, (without crystals, like many of today's clocks), to within 1 second per 100 days.

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SocksOnHands t1_ixcy063 wrote

Ok, sorry. My confusion was from the title saying that it "shown the correct date, time... from 1750". Any clock can be "correct" if it is constantly being corrected by someone.

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DrugChemistry t1_ixcqlgh wrote

Why does it lack crystals? My understanding is that the jewels in a clock/watch movement are placed in places where things spin. The jewels lower the friction between pieces and are hard so they don’t need frequent replacement.

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Duckbilling t1_ixcw4up wrote

"On December 31, 2000, the château’s staff also gathered around the clock: it went straight to the year 3000 and the clockmaker at the château had to push it back!"

https://www.gazette-drouot.com/en/article/the-secrets-of-claude-simeon-passemant-s-clock/35949

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Captain-Griffen t1_ixd41kw wrote

Based on zero research I'm going to tell you it doesn't keep time accurately. It's a mechanical clock.

The TIL is bullshit.

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WilliamMorris420 t1_ixd8qjm wrote

I'm sure that humans keep correctimg the time and planetary movements. The clock has to be wound upnon probably a daily basis and it's impossible for a non-atomic clock to be accurate for thst long. Even a quartz watch (without radio or internet time corrections) will be out by a few minutes each year. And that's without taking into account leap seconds. Which the designer could never have considered as they only started in 1960-1972 and are irregularly placed with only about 6 months notice.

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