Omega Marine Chronometer

The Omega Marine Chronometer was the first quartz wristwatch ever to be awarded certified status as a marine chronometer. The watch was made by Omega SA and developed by John Othenin-Girard and is one of the most accurate non thermo-compensated production watches ever made, keeping time to within 1 second per month [1]

Introduction

The watch was introduced to the market in 1974 under calibre 1511, having an unrivalled accuracy of 12 seconds per year thanks to the revolutionary 2.4 MHz quartz circuit.[2] in 1976 the calibre 1516 Marine Chronometer was introduced with smaller case dimensions and altered movement, although performance remained the same, sales began in 1974 and the watch remained in Omega line up until 1978.

Famous owners of Omega Marine Chronometers have included Jaques Cousteau and Eric Tabarly.

Early development

The first prototypes of the ‘1500 family’ quartz watch (which later developed into the Marine Chronometer) were presented at the Basel Fair in 1970 as calibre 1500, developed by Omega and the Battelle Geneva Research Institute. Known as the ‘Elephant’, there are rumored to have been only five examples of this watch made by Omega.[3][4]

The calibre 1500 ‘Elephant’ (known so because of the design of the movement with two large battery compartments resembling large ears) boasted an accuracy of 12 seconds per year, which equated to 1 second per month, five times more accurate than the beta 21 (the first Swiss production quartz watch) introduced to the market the year previous. The calibre 1500 was Omega’s first in-house quartz movement developed under project leader John Othenin-Girard by SSIH.[5]

The development of the calibre 1500 and subsequent successors cost Omega 30 million Swiss Francs with the sole intention to produce a wristwatch of unparalleled accuracy and performance. This significantly improved performance in time keeping was to be achieved by the development of a circular quartz resonator that vibrated at 2,359,356 times per second (a frequency of 2,359,356 Hz or ≈ 2.4 MHz),[6]

Production watches

By 1974 Omega had developed a more stable production version of the original calibre 1500 Megaquartz. It was released to the market in two versions of 1000 units each.

Calibre 1511: Marine Chronometer, this watch was certified at the Besançon Institute. All 1000 examples were sent to the Besançon in France for testing of their chronometer status and after 63 days of relentless testing (including temperature variation testing) the mean variation was less than two thousandth of a second per day. All 1000 watches were certified as Marine Chronometers and presented with certificates showing their individual performance over the 63-day period.[9]

The Marine Chronometer calibre 1511 was presented in a stainless steel case with integral bracelet with a solid 14-carat gold bezel and 14-carat gold plaque which bears the individual serial number of the movement.

Of the 1000 calibre 1511 watches produced approximately 900 had solid 14-carat bezels and plaque and 100 had stainless steel bezels and plaques, specifically designed for the French market in response to French law at the time requiring visible hall marks on all gold.

The 1511 Marine Chronometer was famously owned by Oceanographer Jacques Cousteau and when introduced in 1974 had a list price of £761, by contrast the Moonwatch was on the market at £124.50 and the now coveted Omega Bullhead was only £114.50.

Calibre 1510: A non Marine Chronometer designated watch with an accuracy of 1 second per month branded as the Constellation Megaquartz.

Further developments

In 1976 Omega refined the design of the Marine Chronometer and the Constellation (previous known as Calibre 1510) with the introduction of the caliber 1516 Marine Chronometer and the documented introduction of the calibre 1515 in Constellation models.[11]

Although widely documented, the caliber 1515 has never been seen as available on the open market, although it does appear in Omega literature but appears cosmetically identical to the calibre 1516 but with a 1510/1511 circuit, however Omega didn't produce a non Marine Chronometer/ Constellation in the smaller case type and as such it is highly unlikely the 1515 went into production watches.

The calibre 1516 movement however was different in design to the 1511, specifically around the main-plate, which was reduced in the size of the movement by 5mm to be able to accommodate the movement in a newly designed smaller Marine Chronometer case. The components of the movement remained fundamentally identical to those of the previous 1511 Marine Chronometer however the screws holes on the main plate (to attach the movement to the case) were removed and replaced by a more traditional movement clamping system.

The case design for the calibre 1516 looked cosmetically identical to that of the 1511 series and used the same 1209/202 integral bracelet, however it was a smaller watch in terms of height by 5mm and included the addition of a sapphire crystal (which had previously been mineral in the calibre 1511). The bezel on the 1516 was also bonded to the case and the 4 screws are purely cosmetic. The 1516 also had a slightly different positioning of the number plaque.

The 1516 Marine Chronometer was produced in 7000 units and sales ran between 1976 and circa 1980, by which point the watch had priced itself out of a much more competitive quartz market and changes in fashions and watch design had limited the Marine Chronometers marketability.

4.19 MHz marine chronometer

In 1978 the French Naval Hydrographic and Oceanographic Service (French: Service hydrographique et océanographique de la Marine or SHOM) requested a quartz chronometer to acquire a reliable autonomous time source independent of external satellite and radio signals. The goal was a timepiece for navigational purposes, like establishing longitude by chronometer, with an accuracy better than 1 second a month. Thirty-six watch and clock companies applied.[12]

Omega's entry used a calibre 1525 movement giving an accuracy of less than five seconds per year and was selected after a year of testing at sea by the French Navy Hydrographic and Oceanographic service.[13]

With the Omega Marine Chronometer wristwatch movement of 1974 as a basis a Quartz Marine Chronometer movement was designed with a high-frequency 4.19 MHz (precisely 222, or 4,194,304 Hz) quartz oscillator that should be capable of an accuracy of approximately ±0.01 second/day. Where quartz elements were usually lens-shaped, this one was barrel-shaped. It had very low ageing properties and a low thermic coefficient, and it was able to function between −10 and +60˚C. The timepiece was tested by the Neuchatel Observatory under rigorous conditions: temperature variations, thermal shocks, magnetic and electric fields, mechanical vibrations etc., which after 47 days of examination earned it the official quartz "Quartz Marine Chronometer" certificate. This is a higher standard than the Marine Chronometer (mechanical) by which standards the 1974 wrist Chronometer was tested.

Summary

In total Omega produced a rumored 10,000 calibre 1500 family watches (around 2000 were in spares), although revolutionary their cost was prohibitive and with the speed of development of quartz during the 1970s Omega wrote off much of the original R&D costs and towards the end of their production run Omega offered the remaining examples to Omega employees at 350 Swiss Francs, 1/10th of the retail cost.[18]

The Marine Chronometers and non Marine Chronometer calibre 1510 watches remain amongst the most significantly important Omegas ever made, one of the earliest quartz watches produced with an excellent accuracy, and to this day a serviced example will still be accurate to 1 second per month.[19]

External links

• 2400 article by Thomas Dick
• Useful Marine Chronometer information
• excellent source of Omega information
• excellent source of quartz and electronic watch information
• www.retromega.com
• www.old-omegas.com
• Megaquartz 2400 article by Thomas Dick