Una pequeña lista
Thermocompensated movements made by Citizen:
Caliber: Citizen Crystron Mega (movement number unknown)
Technology: Single high frequency (4MHz) AT-cut crystal
Annual accuracy: ±3 seconds (We do not know if Citizen recommended a minimum wear time to assure performance to this specification.)
Rate adjustable?: Most probably yes, by the Service Centre in Japan. We do not know the specific adjustment mechanism.
Watches that use this movement:
Citizen Crystron Mega
Note 1: This is the tightest specification ever claimed for a watch!
Note 2: The battery lasted one year.
Note 3: Only 3000 were made. This is not surprising considering the 4,500,000 yen price.
Note 4: This watch is sometimes erroneously referred to as the Citizen Mega Quartz. The picture below shows the correct phonetic translation:
Source of information: The history section of Citizen Japan's website. (Reference 5 below.)
Caliber: A660
Technology: Single 32 kHz crystal (thermocompensation method not known)
Annual Accuracy: ±5 seconds
Rate adjustable?: yes, by the Citizen service centre in Japan
Watches that use this movement:
"The Citizen" (since 1995)
Note 1:This is the tightest specification among currently available watches. (Citizen does recommend daily wear for 12 hours to ensure best performance.)
Note 2: This movement has a perpetual calendar and independently settable hour hand.
Note 3: 'Chronomaster' was added to the dial in 2005, although the name of the line remains The Citizen.
Sources of information: Citizen sales literature, Citizen "The Citizen" owner's manual (Reding)
Caliber A690
Technology: Single 32 kHz crystal (thermocompensation method not known)
Annual accuracy: ±10 seconds
Rate adjustable?: yes, by the Citizen service centre in Japan
Watches that use this movement:
Citizen Exceed (selected models)
Note 1: From pictures in Citizen sales literature of this and the A660 movements, the A690 and A660 are apparently identical. The crystal package in the A660 may be enhanced in some fashion, or it may simply be regulated and adjusted with more care.
Note 2: For the models that have a calendar, the calendar is perpetual.
Note 3: A number of models in this line use the Eco-Drive (solar) power system.
Source of information: Citizen sales literature
Caliber: E410
Technology: not known
Annual accuracy: ±10 seconds
Rate adjustable?: not known
Watches that use this movement:
Citizen Exceed (selected ladies models)
Note 1: This movement is clearly different from the A690, as it is smaller. Also, the date change is gradual vs. near instant.
Note 2: The model that we know about has a perpetual calendar and independently settable hour hand.
Note 3: The model that we know about uses the Eco-Drive (solar) power system.
Sources of information: Owner's manual (Reding), Citizen sales literature
Thermocompensated movements made by ETA:
Caliber: ETA 255.561 (from the ETA Flatline series)
Technology: Dual 32kHz/262 kHz crystals (thermocompensation method not confirmed)
Annual accuracy: ±10 seconds
Rate adjustable?: yes, via digital touch point (user adjustable)
Watches that use this movement:
Longines Conquest VHP (Longines caliber L.276)between 1984 and 1995
Krieger Marine Chronometer (approximately 1994 to 1997)
Note 1: Although not directly confirmed by ETA, we have strong reason to believe that this movement uses the digital count adjustment method.
Note 2: We believe that Longines participatd in the development of this movement, and that they were the first to use it.
Note 3: This movement has an independently settable hour hand.
Note 4: The 255.511 is a companion movement. Functionally, the only difference is that it does not have an independently settable hour hand. We suspect, but do not know, that the timekeeping portion of the movement is identical. We do not know of any watches that used the 511 movement.
Note 5: It is sometimes reported that variants of this movement had a 2.1 megahertz high frequency crystal. This is not confirmed, and the reports are questionable.
Note 6: The Krieger watches were offically certified as Marine Chronometers by Besancon.
Sources of information: Longines caliber number confirmed by Longines service center. The frequencies confirmed by Mr. Jean-Claude Robert of ETA. Functionality of the 511 vs. 561 from ETA technical information sheet.
Caliber: ETA 252.611 (ETA Thermoline)
Technology: single 32 kHz crystal (digital count adjustment method with thermistor)
Annual accuracy: ±10 seconds
Rate adjustable?: yes, by the watchmaker during service
Watches that use this movement:
Longines Conquest VHP Perpetual Calendar (Longines caliber L.546) between 1996 and 2002
Longines Flagship VHP Perpetual Calendar since 2002 (Longines caliber L.546)
Piquot Meridien Octanis Marine Chronometer
Note 1: This movement has an independently settable hour hand.
Note 2: This movement uses a 3 volt 10 year Lithium battery.
Note 3: The Longines Flagship VHP Perpetual Calendar is apparently no longer available, although Longines still lists it on their web site.
Note 4: The Piquot Meridien watches are officially certified as Marine Chronometers by Besancon. They are no longer available.
Sources of information: ETA sales literature, Longines sales literature, Piquot Meridien sales literature, Longines authorized service centre, Longines user's manual
Caliber: ETA 252.511 (ETA Thermoline)
Technology: single 32 kHz crystal (digital count adjustment method with thermistor)
Annual accuracy: ±10 seconds
Rate adjustable?: yes, by the watchmaker during service
Watches that use this movement:
Omega Constellation Perpetual Calendar (Omega caliber 1680)
Omega Constellation Double Eagle Perpetual Calendar (Omega caliber 1680)
Note 1: This movement has an independently settable hour hand.
Note 2: This movement is identical to the 252.611, except that it uses a 1.5 volt, 5 year battery.
Sources of information: ETA sales literature, Omega sales literature, Omega authorized service centre
Caliber: ETA 251.232 (ETA Thermoline)
Technology: single 32 kHz crystal (digital count adjustment method with thermistor)
Annual accuracy: ±10 seconds
Rate adjustable?: yes, by the watchmaker during service
Watches that use this movement:
Breitling Aeromarine Colt Chronograph SQ (Breitling caliber B73)
Breitling Aeromarine Avenger M1 Chronograph SQ (Breitling caliber B73)
Breitling Professional Emergency Mission SQ (Breitling caliber B73)
Note: Breitling has designated all its thermocompensated watches as 'SuperQuartz' (SQ) since2002. For reasons that are unclear, Breitling specifies its SuperQuartz movements to 15 seconds per year, even though we have no evidence that they differ from the ETA Thermoline models which are specified to 10 seconds per year.
Sources of information: ETA sales literature, Breitling sales literature
Caliber: ETA 956.152 (ETA Thermoline)
Technology: single 32 kHz crystal (digital count adjustment method with thermistor)
Annual accuracy: ±10 seconds
Rate adjustable?: yes, by the watchmaker during service
Watches that use this movement:
Breitling Windrider Callistino (Breitling caliber B72)
See note for ETA caliber 251.232.
Sources of information: ETA sales literature, Breitling sales literature
Caliber: ETA 955.652 (ETA Thermoline)
Technology: single 32 kHz crystal (digital count adjustment method with thermistor)
Annual accuracy: ±10 seconds
Rate adjustable?: yes, by the watchmaker during service
Watches that use this movement:
Breitling Aeromarine Colt Quartz SQ (Breitling caliber B74)
See note for ETA caliber 251.232.
Sources of information: ETA sales literature, Breitling sales literature
Caliber: ETA 956.652 (ETA Thermoline)
Technology: single 32 kHz crystal (digital count adjustment method with thermistor)
Annual accuracy: ±10 seconds
Rate adjustable?: yes, by the watchmaker during service
Watches that use this movement:
Breitling Aeromarine Colt Oceane SQ (Breitling caliber B77)
See note for ETA caliber 251.232.
Sources of information: ETA sales literature, Breitling sales literature
Caliber: ETA 955.452 (ETA Thermoline)
Technology: single 32 kHz crystal (digital count adjustment method with thermistor)
Annual accuracy: ±10 seconds
Rate adjustable?: yes, by the watchmaker during service
Watches that use this movement:
none known
Source of information: ETA sales literature
Caliber ETA 988.352 (ETA Thermoline)
Technology: single 32 kHz crystal (digital count adjustment method with thermistor)
Annual accuracy: ±10 seconds
Rate adjustable?: yes, by the watchmaker during service
Watches that use this movement:
Breitling Professional Emergency SQ (Breitling caliber B76)
Breitling Professional Aerospace SQ (Breitling caliber B75)
See note for ETA caliber 251.232.
Sources of information: ETA sales literature, Breitling sales literature
Caliber ETA E20.341 (ETA Thermoline)
Technology: single 32 kHz crystal (digital count adjustment method with thermistor)
Annual accuracy: ±10 seconds
Rate adjustable?: yes, by the watchmaker during service
Watches that use this movement:
Breitling Professional B1 SQ (Breitling caliber B78)
See note for ETA caliber 251.232.
Sources of information: ETA sales literature, Breitling sales literature
Thermocompensated movements made by pre-ETA Omega:
Caliber: Omega 1510, 1511, 1515, 1516
Technology: single 2.4 MHz crystal with AT-cut (lenticular disc shape)
Annual accuracy: ±12 seconds
Rate adjustabe?: yes, via trimmer condenser (user adjustable)
Watches that use this movement:
Omega Megaquartz 2400 (1974 to 1978)
Note 1: Omega stipulated that the watch must be worn daily to perform to the stated specification.
Note 2: Caliber 1510 was the first non-marine chronometer version of this movement. It was succeeded by the 1515.
Note 3: Caliber 1511 was the first Marine Chronometer version. It was succeeded by the 1516. Both were officially certified at Besancon.
Note 4: The hour hand is independently settable. Omega claims this to be the first watch to have this feature.
Note 5: Owners report battery life to be a year or less.
Note 6: One will sometimes see claims that this was the most accurate watch of all time. (Omega makes this claim on their web site.) However, a number of watches then and now surpass it in terms of specified performance.
Sources of information: The history section of Omega's web site and references 6 and 7 below.
Thermocompensated watches made by Rolex:
Caliber: Rolex 5035 (and 5055 for the Day-Date model)
Technology: single 32 kHz crystal using the forced constant frequency (TCVCXO) method
Annual accuracy: around ±60 seconds (Rolex has never stated an official accuracy specification.)
Rate adjustable?: yes, via trimmer condenser (user adjustable)
Watches that use this movement:
Rolex Oysterquartz (1977 to 2001)
Note 1: We are unaware of any other watch using TCVCXO technology.
Note 2: While discontinued, we have heard that Rolex plans to introduce a new quartz movement with update technology and perpetual calendar. More can be read about this in reference 8 below.
Source of information: reference 8 below.
Thermocompensated movements made by Seiko:
Caliber: 9923A
Technology: Dual crystal (The lower frequency crystal is 32 kHz. We do not know the frequency of the higher frequency crystal.)
Annual accuracy: ±20 seconds
Rate adjustable?: yes, via trimmer condenser (user adjustable)
Watches that use this movement:
Seiko Twin Quartz (first introduced in 1978, long discontinued)
Seiko King Quartz
Note 1: Seiko recommended that the watch be worn daily to achieve the stated performance.
Note 2: One sometimes sees the statement in enthusiast literature/fora that Seiko claimed a ±5 second per year performance for the 9923A. This is erroneous, as can be seen in Seiko's literature in reference 9.
Source of information: See reference 9 below.
Caliber: 9F
Technology: single 32 kHz crystal (thermocompensation method not known)
Annual accuracy: ±10 seconds
Rate adjustable: not known, but probably yes, by the service centre in Japan
Watches that use this movement:
selected
Grand Seiko quartz models
Note 1: Seiko re-issued a limited edition of the 'Astron' in 2000 that used a special version of the 9F movement that was rated to ±5 seconds per year.
Note 2: The 9F movement is reportedly designed to run fifty years before it needs servicing.
Note 3: Other Grand Seiko quartz models use the 8J movement. Even less is know about this movement.
Source of information: Japanese retail sites
Caliber: 8F (4F for ladies versions)
Technology: single high frequency 196kHz crystal
Annual accuracy: ±20 seconds per year
Rate adjustable?: yes, by 'pattern cutting' (a non-reversible method)
Watches that use this movement:
Seiko sells many models with this movement.
Note 1: These watches are not thermocompensated. Seiko states that they should be worn 12 hours daily to meet the stated performance specification.
Note 2: These movements have a perpetual calendar.
Note 3: The GMT versions of this movement have an indpendently settable hour hand.
Note 4: Some models have a ten year battery.
Source of information: Japanese retail sites, Seiko authorized service centre, Seiko perpetual calendar (8F) service manuals. (See references 10 and 11 below.)
Caliber: 0634 (mid '70s)
Technology: unknown
Annual accuracy: 120 seconds per year
Rate adjustable?: unknown
Watches that use this movement:
LCD chrono model
Note 1: This movement is one of only two known non-analog movements that is thermocompensated.
Caliber: Y301 (Y302 for date version)
Technology: single 196 kHz crystal
Annual accuracy: ±10 seconds
Rate adjustable?: yes, by pattern cutting (non-reversible)
Watches that use this movement:
Pulsar PSR-10 (by Seiko) no date, discontinued
Pulsar PSR-20 (by Seiko) date, discontinued
Note 1: Seiko states that theses watches should be worn 12 hours daily to meet the stated performance specification.
Note 2: The caliber Y302 uses similar technology, but was rated to ±20 seconds per year.
Note 3: According to numerous reports, the PSR-10 often does not achieve its specified performance.