Citizen’s Hyper-Accurate Quartz Watch Is Ready for the Apocalypse

It’s solar-powered and accurate to ±1 second per year, all without needing a functioning GPS or radio waves.
Source: Hodinkee

Originally published by Jack Forster on Hodinkee. 

I’m not entirely sure why there wasn't more of a hullabaloo about this movement – maybe it's because it wasn't shown during editorial meetings, but rather, placed outside Citizen's booth, where it was easy to miss if you happened to be just walking by, or rushing from one appointment to the next. However, it's easily one of the most remarkable developments of the show and certainly, one of the top technical watchmaking stories of the year: Citizen has developed a light-powered, Eco-Drive movement accurate to just ±1 second per year.

Source: Hodinkee

The movement is cased in a pocket watch, but Citizen says that this not-for-sale prototype is a harbinger of things to come and that we can expect to see the technology in regular production watches in 2019. The pocket watch is pretty compelling though – the case is synthetic sapphire, and the DLC-treated movement is visible through the transparent back. Honestly, I'd give my eyeteeth to own it as is, although I suppose a solar-powered pocket watch might not be the hottest idea. However, it might actually be ok in this instance – Citizen says the watch can run for up to six months in total darkness, so having it live in your pocket some of the time might not be as problematic as it sounds. 

There are several key design points. The first, and one of the most important, is the frequency – a typical quartz watch runs at 32,768 Hz, but caliber 0100 – the name refers to Citizen's 100th anniversary, which is this year – runs at a much higher frequency: 8.4 Mhz, or more precisely, 8,388,608 Hz (vibrations per second). That's considerably faster than the Omega Marine Chronometer from the 1970s, which had a special lens-shaped crystal, and vibrated at 2.4 Mhz (one of these is in the personal collection of Roger Smith, which he shared with us in Talking Watches). Citizen's own Crystron Mega, from 1975, was rated to ±3 seconds per year, at 4.19 Mhz. 

Bulova's Precisionist quartz movement runs at 262 KHz, or 262,144 Hz (interestingly, Bulova is owned by Citizen, and the company obviously sees a future, smart watches be damned, in autonomously accurate high frequency quartz watches). From what I've read you can get off-the-shelf quartz oscillators with frequencies in outlandishly high ranges – 300 Mhz, anyone? – but I suspect such high frequencies would badly tax current battery technology.

Citizen caliber C 0100.
Source: Hodinkee

The second is the cut of the crystal; rather than the usual tuning fork configuration, Citzen is using at AT-cut crystal, which is cut from the larger crystal to a different orientation than conventional tuning fork crystals. The orientation of the cut produces a better resistance to temperature variations (the main cause of inaccuracy in quartz oscillators) and as the vibrations are smaller in amplitude than in a tuning fork crystal, there's less variation in rate due to physical shocks and changes in position as well. There seems to be some sort of software adjustment for temperature rate as well, although the press release is a little less specific on this point.

I mean I know it's coming out in wristwatches next year but frankly I'm more than fine with it just like this.
Source: Hodinkee


In any case, when this tech becomes commercially available, all and any of us whose hearts thrill to the notion of autonomous – not GPS connected, not radio controlled – high-precision timekeeping technology ought to be happy as a clam (which is an expression I've never understood, as every clam I've ever seen has looked morose at best, but you get the idea). I've never in my life stood in line for any new tech product but by gum, I think I'd stand in line for this one. 

Visit for a wider look at their work, and scratch your head, as I did, to find out that this achievement isn't more prominent on their website; if I were them, I'd have laser etched the press release in incandescent letters 10 kilometers across on the surface of the Moon. See you in a year.

The caliber 0100 is 33.3mm x 2.92mm; the prototype, in a sapphire case, is not, alas, for sale.

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