[HN Gopher] Elektrocas HH3 - the most accurate pendulum clock on...
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       Elektrocas HH3 - the most accurate pendulum clock on the planet
        
       Author : tverbeure
       Score  : 99 points
       Date   : 2024-12-31 06:12 UTC (4 days ago)
        
 (HTM) web link (dvaluch.web.cern.ch)
 (TXT) w3m dump (dvaluch.web.cern.ch)
        
       | jesperwe wrote:
       | I passed the "Not like we would not have 150 tons of liquid
       | Helium here" statement off as a joke until I got to the end and
       | realized the author was NOT just another clock renovating
       | hobbyist :-)
       | 
       | Thanks for an enjoyable read!
        
         | Aeolun wrote:
         | He made mention of his position at CERN before that came along
         | I think?
        
       | saagarjha wrote:
       | Really interesting that the clock appears to have detected an
       | actual earthquake and corrected for it!
        
       | MezzoDelCammin wrote:
       | I think it's the first time I see a Czech/Slovak accented "c" on
       | the front page of Hacker News. Well done!
        
         | Squarex wrote:
         | Well another time was back in 2019 [0] with an article about
         | Karel Capek [1] :)
         | 
         | [0] https://news.ycombinator.com/front?day=2019-08-26
         | 
         | [1] https://news.ycombinator.com/item?id=20789755
        
         | urcite_ty_kokos wrote:
         | Also, did you notice Merkur?
        
         | inglor_cz wrote:
         | This was indeed somewhat startling, like meeting an old, well-
         | known dog that just starts mewing at you.
         | 
         | We are used to being the Leprechaun Folk of the West - present
         | almost everywhere, but only rarely seen.
        
           | MezzoDelCammin wrote:
           | Especially if You're old enough to remember what ISO 8859-2
           | was for. One of the standards that everyone knew existed, yet
           | few actually cared enough to correctly implement in practice.
           | I still have a label printer that knows accented characters
           | exist, yet the implementation is "shrink the accented letter
           | to fit the label height with the accent"
        
             | inglor_cz wrote:
             | "shrink the accented letter to fit the label height with
             | the accent"
             | 
             | Ah, memories of youth... not to mention KEYBCS2.
        
       | schobi wrote:
       | I'm glad they only thought about it, but did not implement SF6
       | flooding of the chamber. No need to vent it to the atmosphere
       | just for fun.
       | 
       | But controlling the internal pressure? I would expect that only a
       | small difference would be needed - far from exploding or
       | imploding the clock! Maybe small enough to have a reservoir and
       | control only inlet and outlet valves? This could be done purely
       | without modifications of the mechanism.
        
         | TheOtherHobbes wrote:
         | The biggest danger of explosion/implosion is the change to/from
         | summer time.
        
         | dtgriscom wrote:
         | The control force would be the product of the air density
         | change and the pendulum bob volume. If he increased the
         | pendulum bob volume with a light but fixed-size object (a foam-
         | filled sphere?) he wouldn't need to adjust the density as much.
        
       | progbits wrote:
       | The contrast of the pendulum clock in a wooden cabinet and the
       | sensor mounted on what appears to be Merkur (building toy from
       | 1950s, still available today), with the fiber optic cables and
       | maser is quite something :)
        
         | timeon wrote:
         | Ehm, I'm also using Merkur to extend my cabinets/shelves.
        
       | avidiax wrote:
       | This is in effect a really complicated way of getting an analog
       | readout of his cesium fountain.
       | 
       | The chain adjuster was interesting, though.
       | 
       | Another very accurate pendulum clock (this one solar
       | disciplined): https://en.wikipedia.org/wiki/Clock_of_the_Long_Now
        
         | wbl wrote:
         | Not really: look at the Alan curves. This is a disciplined PLL
         | with a fairly slow loop. Most of the accuracy at short time
         | scales is from the pendulum it's only the long term stability
         | that the atomic clock impacts.
        
       | cenamus wrote:
       | Does anyone know anything about the czech/slovak "flip" clock on
       | the top right of the ~fifth last picture?
       | 
       | I'd love to have something like that for myself
        
         | phreeza wrote:
         | https://youtu.be/8Zd0clYzgj4?si=7T-NXAXfK0IxJ_kG
         | 
         | Google lens identifies it without problems.
         | 
         | Edit: auction link https://aukro.cz/top-stav-pragotron-
         | preklapeci-hodiny-cpj-06...
        
           | cenamus wrote:
           | Thanks! But seeing that price, probably cheaper to build one
           | myself
        
         | timeon wrote:
         | > the czech/slovak "flip" clock
         | 
         | Seems to Czech. Slovak would use "Januar" instead of "Leden".
        
           | cenamus wrote:
           | Ahh right, only the czechs revived the pre-christians terms!
        
       | metalman wrote:
       | The plausible gravity compensation mechanism idea,got me but
       | good. Which if implimented could achive the ideal of the clock
       | remaining exactly as it left the factory, but with 1sec/158
       | million year accuracy. For the convieneince of keeping the clock
       | in your office, would require incorporating the building into the
       | gravity compensation mechanism.Building codes might prove to be
       | the biggest challenge.
        
       | kristjank wrote:
       | The chain-and-cup adjustment is so simple, yet so effective. Such
       | an elegant solution
        
       | withinboredom wrote:
       | I'm just thinking of the discussion in the IT department:
       | 
       | A: He wants what?
       | 
       | B: A cable from the cesium to his office, for some ancient clock
       | he got off ebay.
       | 
       | A: These scientists man...
        
         | bayindirh wrote:
         | I work with some people at CERN on a project.
         | 
         | What I got away is, the answer from IT would be "that's a cool
         | project. Just ask your department head, and if they say OK,
         | consider it done".
         | 
         | CERN still operates with and fueled by curiosity, and that's a
         | good thing.
        
           | tgsovlerkhgsel wrote:
           | > Just ask your department head
           | 
           | That'd already be a lot more bureaucracy than I'd have
           | expected.
        
             | bayindirh wrote:
             | It's a lot of bureaucracy, yes, but considering the
             | planning they do and the scale of the projects they
             | undertake, it's understandable.
             | 
             | They are massive in every aspect.
        
       | zokier wrote:
       | It seems bit odd to call it most accurate pendelum clock if the
       | accuracy stems from being disciplined by atomic clock. To me the
       | interesting question would be how far can you push the
       | freestanding accuracy of a pendelum clock.
       | 
       | That is not to say this isn't a neat project in it's own right,
       | it is, but just picking on the terminology.
        
         | stavros wrote:
         | I agree, it's not a clock if it can't keep time on its own.
         | It's a really cool project, but the clickbait title disappoints
         | unnecessarily. "I made an NTP pendulum clock" would have been
         | accurate and still extremely cool.
        
         | jgalt212 wrote:
         | better title
         | 
         | Elektrocas HH3 - the most accurate atomically assisted pendulum
         | clock on the planet (cern.ch)
        
         | technothrasher wrote:
         | Pendulum clocks in general need to be periodically rated
         | (length of pendulum adjusted) due to variations in temperature
         | and pressure in order to achieve maximum isochronous movement.
         | All this guy has done is created an automatic rating system.
         | Otherwise, it operates the same way as most any other pendulum
         | clock. So I think the "most accurate pendulum clock"
         | description is fair (assuming it is the most accurate).
         | 
         | I've had ideas for a while for similarly adjusting a pendulum
         | clock from an NTP server, though I was going to add an extra
         | gear to the motion train that would adjust the hands slightly
         | every twelve hours. But that seems more like "cheating" that
         | this rating system.
        
         | KaiserPro wrote:
         | So if you want the most accurate pendulum clock, then you'll
         | need the vacuum flask one:
         | https://www.rmg.co.uk/collections/objects/rmgc-object-79649 or
         | its german counterpart:
         | https://theregulatorclockcompany.com/riefler/
        
       | stavros wrote:
       | I wonder if it would have been easier to have a small
       | electromagnet in the base to pull the pendulum down either before
       | or after the lowest point, as necessary. Wouldn't that have been
       | a much simpler solution?
        
         | phreeza wrote:
         | Mentioned in the article, this was considered too boring!
        
           | stavros wrote:
           | Ahh thanks, turns out I missed it because it was a small
           | sentence right over the big equation that my eyes glazed over
           | :P
        
       | mrlonglong wrote:
       | "Changing the 2, or p is difficult even for CERN". Brilliant!
        
       | hsuduebc2 wrote:
       | I understant it only partially but still loving it!
        
       | blacksmith_tb wrote:
       | There's something very satisfying about electromechanical clocks,
       | I think it may be the combination of math-y/steampunk-y gear-
       | driven timekeeping with actual accuracy. I have always thought
       | once I Made It Big I'd get myself a Seiko Spring Drive watch[1] -
       | hasn't happened yet...
       | 
       | 1: https://www.seikowatches.com/us-
       | en/customerservice/knowledge...
        
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       (page generated 2025-01-04 23:01 UTC)