The most accurate wristwatch ever?

[Otis]

Came across this little bit of info earlier this week, thought I'd share it.
Once again, it shows just how well-made some of the brands that are considered 'low-end' are.

The Citizen Citizen Crystron Mega or 'Mega Quartz'. c.1975!



Considered by many as the most accurate wristwatch. Whilst most quartz watches were within 15seconds per month, the citizen mega quartz/Citizen Crystron Mega was accurate to 3 seconds per year. Per year, people!
A bit of info on it's 'thermocompensated' quartz movement:
Stability in a quartz watch's rate, comes down to the cycles/beats of its resonator, the quartz crystal. Apparently, the crystal actually moves, many many thousand times per second. The fact that they have such a high oscillation rate negate traditional factors that effect a rate, ie: arm movement, watch position, gravity and so on. However, one small drawback appears to be that it is affected slightly by temperate, which has been the greatest cause of rate difference in quartz watches.

One way of reducing error rate is to keep the crystal at a constant temperature, as is done with some laboratory instruments by keeping them in an oven of sorts. Now, carring an oven is not only uncomfortable, but also impractical. But, it seems that just wearing your watch on your wrist has a similar effect! The temperature of your body varies less than ambient temperatures, therefore your watch is always next to a (relatively) constant temperature. Also, those clever buggers who make the crystals have used their physical properties to best advantage: at a particular temperature point, the various idiosyncrasies within the crystals start to cancel eachother out. This point sits around 28 degrees celsius, or 'wrist temperature'.
HOWEVER.... if the temp varies greatly, the rate is affected. This is where 'thermocompensation' kicks in:

Among many methods used, the Citizen in question had a very, very high frequency crystal (4MHz). I don't really get it, but I'll try and simplify it...
They also have a different crystal orientation, and the relationship between these enables a broader range of temperature over which the rate is constant.
There are a few different methods, one of which the Oysterquartz utilised, but I really cant explain them clearly....so, check out this link, a damn good read. It talks about the OQ as well:

http://forums.watchuseek.com/showthread.php?t=2087

Back to the citizen.... IMO it's a ugly looking, watch, it was made with case and band in one piece, 18K gold, the battery lasted 1 year, only 3000 were made and it cost more than $15,000. But, what a hell of a piece of engineering. Reading about all of this really was interesting, and gave me a lot of respect for the quartz phenomenon!


(Apologies to all if I screwed up in trying to explain it, i'm no scientist and it bloody confusing at times!)

[padi56]

Excellent post Otis, done a bit on the the Citizen quartz watches a bit back,and on the Seiko +- 5 secs a year,but they claimed with a bit of adjusting 2 seconds a year was possible.But the price turned a lot of people off including the Japanese.Now myself have great respect for the Seiko Grand fantastic mechanical movement and as good as any from the swiss/European brands But when you think of mechanical watches today and quite a few lower market quartz watches.Are not as accurate as a watch made almost 300 years ago by John Harrison,sort of puts a different perspective on things.But I still think the quartz technology,today lies firmly in the Japanese hands and respect there quartz watch knowhow in every way.

[Otis]

Originally Posted by padi56

Excellent post Otis done a bit on the the Citizen quartz watches a bit back,and on the Seiko +- 5 secs a year,but they claimed with a bit of adjusting 2 seconds a year was possible.But the price turned a lot of people off including the Japanese.Now myself have great respect for the Seiko Grand fantastic mechanical movement and as good as any from the swiss/European brands But when you think of mechanical watches today and quite a few lower market quartz watches.Are not as accurate as a watch made almost 300 years ago by John Harrison,sort of puts a different perspective on things.But I still think the quartz technology,today lies firmly in the Japanese hands and respect there quartz watch knowhow in every way.

Yes, that watch by Harrison was constantly at the back of my mind while I was reading that, what an amazing work of art and genius that was.
I wonder, is it possible to almost look at the quartz and mechanical watches in two different lights? One is the pursuit of engineering excellence, and once is the science of precision?

hmmm... work must be getting to me, sound like a bloody copywriter there!

[padi56]

Yes agree in-fact perhaps the quartz engineering more difficult to achieve,and certainly more costly to make and design.Than the standard run of the mill quartz watch movement.

[JJ Irani]

Great article, Otis....but this OMEGA has always been considered as the world's most accurate watch...here's the link:

http://home.xnet.com/~cmaddox/omega_...artz_2400.html

[padi56]

Originally Posted by JJ Irani

Great article, Otis....but this OMEGA has always been considered as the world's most accurate watch...here's the link:

http://home.xnet.com/~cmaddox/omega_...artz_2400.html

Sorry JJ cannot agree with that perhaps then the Omega was about + 10 secs a year.In 1975 the Citizen +3 seconds a year,and Seiko claimed with adjustment they got theres + 2 seconds a year.

[Otis]

Originally Posted by JJ Irani

Great article, Otis....but this OMEGA has always been considered as the world's most accurate watch...here's the link:

http://home.xnet.com/~cmaddox/omega_...artz_2400.html

Still a very accurate watch, but it did have a greater variation than the citizen. Interestingly enough, it used the same type of thermocompensated, AT-cut (the cut orientation) quartz crystal as the citizen. Looks like it's a fair whack slower in its oscillations though.

But, I would much rather wear that!

Originally Posted by padi56

Sorry JJ cannot agree with that perhaps then the Omega was about + 10 secs a year.In 1975 the Citizen +3 seconds a year,and Seiko claimed with adjustment they got theres + 2 seconds a year.

I agree Peter - I think this one was rated at +12 seconds per year.

Quite a few watches better than that including the Citizen.......

[Rockrolex]

Of course, there's this one - accurate to within 1 second in 10K years.

[mailman]

Don't forget about the Atomic G's

[mike]

Originally Posted by mailman

Don't forget about the Atomic G's

My most accurate

[padi56]

Would agree but not really the same technology,one is regulated and controlled by radio waves.The other just relies on its power,and quartz crystal but in reality whats in a few seconds or god forbid a minute between friends.

[mailman]

Originally Posted by padi56

Would agree but not really the same technology,one is regulated and controlled by radio waves.The other just relies on its power,and quartz crystal but in reality whats in a few seconds or god forbid a minute between friends.

I see JJ hasn't read this thread yet. He'd be all over us about accuracy.

[JJ Irani]

Originally Posted by mailman

I see JJ hasn't read this thread yet. He'd be all over us about accuracy.

Looks like YOU haven't read this thread properly, tosser. Look above!!

[mailman]

Originally Posted by JJ Irani

Looks like YOU haven't read this thread properly, tosser. Look above!!

Sorry. I was confused due to the fact that you didn't make your usual put us to sleep reply