That comes out to about 30ppb, and this is a pocket watch so they dont seem to depend on the temp stabilization of being attached to a human wrist.
https://www.ablogtowatch.com/wp-content/uploads/2018/03/Citizen-Cal-0100-Eco -Drive-Movement-04.jpg Ive been reading about the new watch that contains this crystal for about a month, but just saw some more detail today --- AT-CUT QUARTZ CRYSTAL OSCILLATOR While AT-cut quartz crystals have indeed been in production and use since as early as 1934, the technology is more common in larger applications and not necessarily wristwatches. To address the needs of individuals seeking only the most accurate performance in a wristwatch, Citizen sought to apply and optimize this available technology in a way that could serve watch consumers on a more direct and personal level. When working to reach the accuracy of the Cal.0100, Citizen opted for an AT-cut quartz oscillator instead of a more traditional tuning fork shape (XY cut). Perhaps most notably, AT-cut variations allow for greater temperature tolerances, specifically in the range of -40°C to +125°C. Additionally, this configuration allows for reduced deviations caused by wearer orientation, which can cause significant changes in accuracy that aren't negligible when attempting this kind of performance. As a result, wearers will not have to worry about errors caused by spatial orientation and positioning becomes less of a concern. The same can be said about durability, which Citizen also improved upon in conjunction with the AT-cut oscillator. After all, shock experienced in day-to-day situations could easily prove detrimental even for quartz movements. And when the goal is an annual accuracy of ±1 second, that just isn't acceptable. https://www.ablogtowatch.com/citizen-cal-0100-eco-drive-watch-movement/ --- Is this possible with an MXCO running across this wide temp range? How are they compensating for aging at this level of precision? Thanks! _______________________________________________ time-nuts mailing list -- email@example.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.