Talk:Shortt–Synchronome clock

Rewrote and expanded

Completely rewrote and expanded the current inadequate stub, added image and citations. Removed "no citations" tag. --Chetvorno^TALK 16:34, 30 December 2009 (UTC)

Additional Info, including Circuit Diagram from an Original Synchronome source

Some images located here might be interesting and suitable for inclusion. I am not certain about the copyright status of this material. It is a pamphlet which I was given when I visited the Synchronome Company in London in the early 1960s when I was an undergrad at Imperial College. The company is no longer in existence, but its assets might belong to some other company. On the other hand it is almost certain that this document is more than 50yrs old, so the copyright might have expired.

http://g4oep.esy.es/synchronome/synchronome.html

Andy G4OEP — Preceding unsigned comment added by 77.96.60.31 (talk) 11:35, 6 March 2014 (UTC)

That pamphlet is GREAT, thank you so much for posting it. It will be an excellent primary source of information. Like you, I'd really like to see some of the pictures put in this article, especially the schematic diagram on p. 7. However I don't see a publication date in the pamphlet. I would be willing to bet it's in the public domain as you say, but without a publication date, uploading it to WP or Commons will be problematic. --Chetvorno^TALK 03:41, 7 March 2014 (UTC)

If it is at all helpful I can say for certain that I was given the pamphlet in 1964, so it is at least 50 years old G4OEP — Preceding unsigned comment added by 77.96.60.31 (talk) 09:08, 7 March 2014 (UTC)

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"Mine is better than yours"?

It's interesting how wide the claims of accuracy differ: For the Riefler escapement, we find claims of 0,0004 s/d (German WP) = 1/7 s/y to 10 ms/d = 4 s/y (English WP). Here, we read about 1 s/y to 1/12 s/y. Interestingly, the NIST used a Riefler clock, and Riefler outnumbered Synchronome by about 7:1 at observatories. But of course, they were purely mechanical, whereas Synchronome was already electrically driven - yet, in the (I assume) very conservative time-measuring community (by necessity: Doing a business where it takes years to even find out about errors, much longer for finding their causes), it would take decades until a "new" invention would get a footing ... and then, electronics and quartzes came along. --User:Haraldmmueller 08:36, 30 May 2020 (UTC)

Good point. Part of the problem is that with a primary physical standard (as these clocks were) there is nothing more accurate to compare the standard to, to determine how much it varies. The rotation of the Earth (as determined by star transits) was the previous primary time standard, but both the Riefler and Synchronome clocks revealed slight variations (nutation) in the rotation rate of the Earth, so they were actually more accurate time standards than the Earth. With a primary standard all you can do is compare separate synchronized standards over time to see how much they vary from each other. As you say, this takes a lot of time. Naval observatories had 'ensembles' of precision clocks which they compared with each other, and with clocks in other naval observatories. The Boucheron atomic clock measurement makes clear that the accuracy of 1 sec/year that was quoted for the Synchronome clock while it was used, was not the clock's actual variation but was simply the limiting accuracy with which time could be measured with the manual methods used in those days. I don't know if the same was true for the Riefler; I guess it's possible that it was also more accurate than the quoted 10 ms/day. I wonder if anyone has done a similar measurement of a Riefler clock to see how accurate it really was? --Chetvorno^TALK 00:10, 31 May 2020 (UTC)