WatchUSeek Watch Forums banner

1 - 16 of 16 Posts

·
Registered
Joined
·
1,246 Posts
Discussion Starter · #1 ·
So according to this article...
https://www.watchtime.com/featured/...va-citizen-chronomaster-omega-grand-seiko-9f/

(which I see some experts here on this subforum do not like) this Bulova that I own is a HAQ. Is that correct?
I think it has lost 3 seconds in about 4-5 months. My real question is about the next watch after this one.




Okay, so then I have this one. It is within 1/2 second three months after I set it last. At that time I think it had lost 2 or 3 seconds over 6-7 months. Seems like HAQ to me. Are there official regulations or standards that define the meaning of HAQ, perhaps governing what (at least Swiss, or maybe Japanese) watch companies can call HAQ? Or is it just an ideal or target that is generally known? If this Omega is not an HAQ, then it just happens to be a very accurate watch. But I'm interested to hear what the experts here have to say about it. Thanks, Mike.

 

·
Registered
Joined
·
351 Posts
COSC for quartz is ±0.07 seconds per day which is ± 25.6 seconds per year.

The best production HAQ are specced at 5 seconds per year.

Some people say 10 seconds per year is HAQ, but for me COSC or better is fine.

As far as I know, Omega never put a thermocompensated quartz movement in an Aqua Terra.
Sometimes you just get lucky, depending on the temperature you store the watch at and how stable the crystal is.

Yours looks like a 2517.50.00, which has the Omega 1538 movement. This is apparently an ETA 255.461, which is not thermocompensated.
 

·
HAQ and AW moderator
Joined
·
7,776 Posts
In the current era <10 s/y although we discuss watches with greater deviations. Really need TC for a HAQ, although some higher frequency watches can achieve HAQ specs.
 

·
Premium Member
Joined
·
9,466 Posts
Baker's article has numerous flaws and omissions.

The Bulova is, as noted in that article, not HAQ; it's got good accuracy but it's closer to 5 SPM.

When we mean HAQ, we speak about an accuracy assertion to which, if desired, the manufacturer can be held. There is no fixed definition, by any means...heck, the term itself is colloquial. The standard we've used here is, as Baker noted, historically 10 SPY. However, as hughesyn noted, the COSC quartz chronometer standard, which a layman will take as "highly accurate quartz" is 25 SPY. And we've also talked about the high-freq Bulovas, which don't quite manage that. (Oh, and the COSC requirement includes TC, and IIRC we don't think Bulova includes it.)

So, most of us aren't too pedantic about it. At least until the Citizen 0100 movement hits. Then we'll see. :)


But hey, you've got some nicely behaved pieces, so enjoy them. I'd not be surprised that the Omega would behave very well, as long as it stays within temps.
 

·
Registered
Joined
·
1,246 Posts
Discussion Starter · #5 ·
Thanks for all the replies. I learned a lot.

I generally wear the Omega 1-2 days/week. Otherwise it sits in my drawer. This pattern seems to keep it spot on.
The Bulova gets worn less, maybe 1-2 days/month.
 

·
Registered
Joined
·
3,146 Posts
I'm not sure where these various bloggers are getting their accuracy specs from for Bulova. Bulova seems to be pretty vague on these numbers, and bloggers are all over the place on the specs. The one thing that I have seen over the last three or so years on these forums is that most if not all have performed much better 1 min/yr, typical performance is closer to COSC.

As far as what qualifies as HAQ, it seems there are two options, move what the acceptable cut off based on the current technology, and eliminate what was once considered HAQ, 10 s/yr wipes out a lot of players, or once it is admitted into the HAQ club like say that old Rolex, it remains.
 

·
Registered
Joined
·
36,311 Posts


Have this^^^ Lobster as well and it is pretty much dead nuts accurate, but lacking TC = temperature compensation, all Bulova are not technically HAQ even tho many are accurate enough.
 

·
Registered
Joined
·
3,146 Posts
I thought TC is simply any method employed correct for temperature change. Documentation says that Bulova addresses temp in the circuitry (Lombardi, Arnstein). That sounds like TC to me.

Temp correction can also be achieved via the crystal cut, and possibly by frequency. I'm not sure how much TC is considered adequate in a non COSC certified watch, in COSC it's 0.2 s/day at +/-15C, not sure what Longines, Bulova, Citizen, and Seiko allow for.
 

·
Registered
Joined
·
3,146 Posts
Picking a specific crystal cut sounds more like thermal insensitivity.
Good point. So a crystal cut that is precise and inherently more stable across the specified COSC temperature range that doesn't require compensation to meet specs, would be a superior product. Clearly any process that doesn't require intervention, adjustment, or compensation to produce accurate results is preferred.

Since COSC is a European thing if eta produces a thermally insensitive movement that doesn't require TC, would COSC certify it, and would the HAQ forum recognise it.
 

·
Premium Member
Joined
·
7,700 Posts
Good point. So a crystal cut that is precise and inherently more stable across the specified COSC temperature range that doesn't require compensation to meet specs, would be a superior product. Clearly any process that doesn't require intervention, adjustment, or compensation to produce accurate results is preferred.

Since COSC is a European thing if eta produces a thermally insensitive movement that doesn't require TC, would COSC certify it, and would the HAQ forum recognise it.
COSC requires TC for certification, so no, COSC would not certify it.

As to whether the HAQ forum would recognize it... case by case.

HTH
 

·
Registered
Joined
·
2,191 Posts
Good point. So a crystal cut that is precise and inherently more stable across the specified COSC temperature range that doesn't require compensation to meet specs, would be a superior product. Clearly any process that doesn't require intervention, adjustment, or compensation to produce accurate results is preferred.

Since COSC is a European thing if eta produces a thermally insensitive movement that doesn't require TC, would COSC certify it, and would the HAQ forum recognise it.
There is a big difference between requiring initial intervention, etc., and making it available. The effect of ageing of crystals and associated circuitry is reasonably well established, and without adjustment many watches will be expected to drift away from their original accuracy as they get older. Also, there is as yet no such thing as 'perfect' temperature insensitivity, so without adjustment there would be no way to correct a watch for the effect of the owner moving from the tropics to the poles. My experience is that modern TC movements from ETA are no less temperature sensitive than those of 30 years ago. I don't think that a set-in-concrete performance would be very preferable.

If and when ETA (or any other company) produces a perfect quartz oscillator, COSC (Swiss-only by the way) will need to upgrade their certification process to deal with it and produce meaningful data. We are still a long way from that happy day.
 

·
Premium Member
Joined
·
9,466 Posts
Been a while since I read up on the various cuts, but they have some other issues. This is a comment about the SC cut:

This cut uses a double rotation to the basic axes: 35°15' and 21° 54'. Whilst this cut provides excellent ageing and stability as well as a low phase noise performance, it has a higher ESR and also it is more susceptible to spurious resonances. One of the difficulties with the SC cut is that it creates difficulties during manufacture because the requirement for compound angles as used in the SC cut adds cost in terms of measuring the angles and then maintaining them during the subsequent lapping and polishing processes. Tolerances for the SC cut are tight. They typically require a tolerance of ±10" as opposed to ±30" for an AT cut.
ESR is equivalent series resistance, so I take it this implies higher power consumption, but from the sound of it, it'd probably be prohibitively expensive for a consumer-level crystal.

Point is, there's probably no such thing as a perfect oscillator. Change A to gain B, but C and D crop up.

But, yeah, when some other approach comes up that's got better thermal insensitivity, there'll have to be new standards written.
 

·
Registered
Joined
·
3,146 Posts
Guess I wasn't clear. AFAIK isn't ageing associated mostly with contamination, or gases and other impurities in the crystal. TC isn't going to make a difference with these issues. I also agree that there is no perfect cut that is temperature insensitive. Just looking for one that can meet the COSC specs, 0.2 s/day at +/- 15C. I agree you would have to be able to adjust the precision based on on operation at temperature extremes, but you wouldn't require TC. That's built in.

Not my field of study but for the last 30 years the bulk of the HAQ watches are AT cut tuning fork design. No telling what an ultra pure synthetic quartz crystal cut with a bt, ct, gt, ..et al. cut, optimum angle, with two, three, four, .et al. prongs, paired with clean power and advanced IC chip.

Maybe that 1 s/yr Citizen is packing something special.
 

·
Banned
Joined
·
3,654 Posts
...If and when ETA (or any other company) produces a perfect quartz oscillator, COSC (Swiss-only by the way) will need to upgrade their certification process to deal with it and produce meaningful data...
Exactly! The current COSC for quartz would not certify non-thermocompensated high-frequency (MHz-range) Swiss watches like the Omega 2.4MHz or Omega 4.19MHz though these watches would easily pass the COSC-tests but instead of thermocompensation they would use thermal-insensitivity as the scheme to achieve high-accuracy/precision. In the current wording of the COSC for quartz the reference for active thermocompensation is unnecessary as thermal-insensitivity can be just as effective by itself to achieve similar result as thermocompensation. That unprofessional attitude (from a scientific point of view) from the COSC authority indicates that the whole thing is mostly about marketing (the banning of non-Swiss movement from the COSC certification is also pure marketing indeed!).
 
  • Like
Reactions: chronos76
1 - 16 of 16 Posts
Top