Defining 'High Accuracy'

I shall not presume to offer a 'written-in-stone' definition of 'high accuracy', and there are perfectly valid interpretations that differ from mine.

One of the broadest approaches is to use the COSC requirements for a quartz chronometer. COSC, after all, is looked upon as the Authority on precision. By the latest COSC standards, this means a watch would need to employ some method of thermocompensation (TC) and deliver a seconds-per-year (SPY) performance of around +/-25.

The pre-1990 COSC standards were even more lax than this, and even my Swatch Jelly Fish made the grade, back then. Under the old standard, watches didn't need TC and could be off by as much as a minute per year.

On the WUS High Accuracy Quartz forum, many regulars don't consider 25 SPY to be particularly special and some won't look twice at a watch unless it delivers 10 SPY or better.

And what about TC? That isn't defined by COSC and debate rages about whether this or that particular approach truly constitutes thermocompesation.

And then what about a watch that uses a high frequency movement and has a rate trimmer so that it consistently delivers sub-10 SPY results year after year? High frequency movements are often considered to be 'thermo-insensitive' (TI) and not 'thermo-compensated' and so it may be considered that they fail to meet the criteria of 'HAQ' watches. But a Seiko Dolce with an 8J41 movement is counted as HAQ on the basis of having TC and being spec'd to 10 SPY... even though the rate probably cannot be adjusted and once time has taken its toll on the crystal it will never again be able to deliver to spec..

All quartz crystals age and as they do so their performance changes. A TC, 10 SPY HAQ that cannot be adjusted will eventually be no more accurate than an ordinary quartz watch. So what is it that makes a watch a 'HAQ' in the relatively small world of high accuracy collectors? In short, it would be any watch with a factory spec. (not just lucky performance) significantly higher than the 15 to 30 seconds per month of 'normal' quartz watches, or one that was so designed but which may never have been assigned an official factory spec. (such as a prototype).

So, which of my watches have I included in the HAQ category?

I have gone with anything that was spec'd to 20 SPY or better at the factory, regardless of whether it can still achieve that, today. I have included high frequency (TI), thermistor (TC), dual oscillator (TC) and twin mode (TI) watches, even where their rate cannot be adjusted. It's a very 'broad brush' approach, and it allows me to investigate and appreciate a wide range of different movements. As 'special considerations' I have also included the Swatch Jelly Fish Chronometer because it has a COSC certificate, the Omega prototype because of its 4 MHz oscillator, and the Accutron II because it uses the same movement (albeit 'modified') as the 10 SPY Precisionist.

Of course, if you are a casual visitor to this site, then you may well wonder what the big deal is with HAQ, anyway? I try to answer that, here.

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