Reply With QuoteThat's why they'll usually specify 'COSC' in the description, or whatever other relevant testing authority. If it doesn't, assume it's not certified by one of those...but it doesn't mean it won't keep as good time just because it isn't certified!
A definition I found on-line is:
"If a watch is referred to as a chronometer, it has passed intense precision tests over a 15-day period and has obtained an official rate certificate from the COSC, which is the Official Swiss Chronometer Testing Institute. ... If a watch is referred to as a chronometer, it is a superior timekeeper and is very accurate"
Presumably many watches are loosely described as Chronometers and they are not within the above definition???
Last edited by BillN; 24th September 2019 at 10:20.
That's why they'll usually specify 'COSC' in the description, or whatever other relevant testing authority. If it doesn't, assume it's not certified by one of those...but it doesn't mean it won't keep as good time just because it isn't certified!
For me having cosc certification means the daily accuracy is between -4 to +6s a day. But is there a validity timeframe? Can't imagine a cosc watch running to specs after 10 years. Plus if parts are replaced, does it lose its cosc certification?
Anyways, to me it's all a marketing gimmick. I'll just call my watch.. a watch.
You will still find a lot of people (including people who should know better, like the people who write auction lot descriptions) getting their terms wrong and describing a chronograph as a chronometer.
It should be a very tight set of criteria - COSC certified watch = chronometer in recent times, or in earlier times other authorising agents would have qualified ships' chronometers and so forth.
But the term seems to have been (wrongly) diluted.
Dave
Just looked up the definition of a Chronograph
"A chronograph watch is simply a timepiece that can be used as a stopwatch in addition to its standard display watch capabilities. A chronograph watch will have dials that keep track of seconds, minutes and hours"
I'm sure quite a lot of people get confused, (not on here obviously!!!), between the two terms
one the other way
https://www.ebay.co.uk/itm/Vintage-R...cd984e9ebd61c6
Last edited by BillN; 24th September 2019 at 10:40.
The idea that an English word means whatever the Swiss decree is amusing. The Germans have their own definition. Should we disdain any German use of the word Chronometer just because their standards are not identical to the Swiss standards?
Last edited by Der Amf; 24th September 2019 at 10:42. Reason: link
Not wishing to go off on too much of a tangent, but where do quartz watches stand as regards these descriptors?
Surely something like a G Shock GW5610 meets the criteria for chronometer and chronograph? Or does this only apply to mechanicals?
COSC have separate criteria for quartzOriginally Posted by Velorum
At time of testing, a bit like an MOT, your car is road worthy at the time of testing, that's all. Now, Manufacturers who believe in their product will then add a long warranty, so during that period if your watch goes out of COSC it can be adjusted / regulated back within spec.
A very old article from Timezone explains.
I can't think of a modern watch advertised as a "chronometer" that is not officially COSC tested.
The certification demonstrates that movement is capable - the onus is on service agents to ensure it is tested to meet standards on service.
In practice it is normally only regulation that needs altering for on the wrist wear.
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The Germans may have their own lab and standard, but only German watches are allowed to be tested there (and their DIN standards are almost identical to the Swiss ISO anyhow, so it makes no difference).
Omega has produced a new, non-COSC standars with METAS in order to differentiate itself from Rolex, and tests to that. It is a shorter but more challenging test.
Seiko got the hump (quite rightly) with the Swiss closed shop and have made their own tests, which are even tighter than the Swiss and German ones.
But the only one that is an ISO (the I being International) is the COSC standard, which is why most people use it as the standard by which they differentiate their watches from more run-of-the-mill ones.
A chronometer is simply an accurate timepiece, accurate despite environmental variation. A Chronometer is a COSC certified one. When you right the rules (as they did) you get to tell people how to play the game. The Swiss, for better or worse, wrote the rules, in the early 1970s. So it is their game to control.
Then of course there's Omega with METAS certification.
The German company Hentschel happily use the word: https://hentschel-hamburg.com/modelle/h1.html
(So do Parnis, but I think I can be forgiven for not finding a link for them)
I tried reading the testing regime and exact definitions recently......after a couple of minutes I decided I didn`t trust the source of info so I gave up, there seemed no point in expending the mental energy to decipher something that may not be correct! I really ought to persevere with this purely out of interest, but I know it won't make a scrap of difference to how I work or how I judge watches.
It's the -4 to +6 thing where I've seen conflicting definitions, or possibly conflicting translations. My 'working understanding' is that a watch must have a rate between -4 and +6 in the 5 tested positions to meet COSC, but this isn`t exclusive, there are other criteria. However, if it doesn`t meet the -4 to +6 it isn`t going to pass, that's my interpretation and that's what I work towards. If I can get all positions to range from -4 to +6 I`m happy.......but I`m even happier if the watch performs well and passes my own tests, based on 16hrs wrist wear and 8 hrs dial-up overnight.
Read my post last week (Constellation Timekeeping), I`ve quoted the positional variation and by my definition it doesn`t quite meet COSC (biggest variation is 14 secs, should be 10) but the watch has only lost 5 secs over a week! Clearly, it'll run between -4 and +6 but it won't meet COSC! As the watch is 47 years old I`m not concerned, but if it was a 5 year old chronometer-rated watch I would be disappointed with the figures.
There's a distinction between adjustment and regulation. Adjustment makes a watch an inherently better watch by improving the precision, regulation is merely altering the rate to make the best of what you've got.
Interesting
Thanks for the link
Originally Chronometer just meant instrument for measuring time.
The COSC thing is relatively recent, but generally means a particularly accurate (COSC have their definition, Omega theirs and don't Rolex have their own now too?) timepiece.
M
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Breitling Cosmonaute 809 - What's not to like?
Chronometer is an instrument used to measure time and any watch can call itself so.
Certified chronometer, COSC etc are obviously different terms.
There are chronometers and then there are marine chronometers
A Chronometer is a watch that performs within the parameters of the ISO 3159 standard - "Timekeeping instruments — Wrist chronometers with spring balance oscillator"
Last edited by MrBanks; 24th September 2019 at 16:35.
I read somewhere the other day that only Swiss watches can be certified by COSC - whatever Swiss might mean in this modern world! Does this mean that for watches made anywhere else, you can use the Chronometer freely???
Not really true, Bremonts are all chronometers
A Chronometer is what I use to boil my Eggs
Only Swiss made watches can use COSC but anyone can use the word Chronometer if they are making chronometer certified movements. There's no copyright on the word chronometer.
No, but there is effectively on Chronometer - the capital denotes the official certification
If your watch conforms to the ISO 3159 standard you can call your watch a chronometer.
Then start the sentence with 'chronometer'.
The title of the thread is "What is a Chronometer"
I was thinking of manufacturers describing their watches, though thread titles are often capitalised
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