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Omega calibers – The super-powers behind the Omega watch faces Part 3

May 03, 2021 5 min read

Omega calibers – The super-powers behind the Omega watch faces Part 3

Part 3: Legendary Omega calibers

As you could see in our past articles, the world of Omega calibers is a vast universe of wholla lotta movements so now we’ll cover some of the core, or let’s say calibers of the utmost importance when it comes to Omega.

The first Omega caliber was introduced in 1894 and was called the 19-ligne. It was produced by the sons of Omega’s founder, Louis Brandt. Louis-Paul and César Brandt nicknamed it simply Omega caliber (by the Greek letter) but the 19-ligne stems from its size, where 1 inch equals 12 lignes (1 ligne = 2.26 mm). Where this caliber changed history is the fact that it was made through an industrialized environment. It was made in series and had interchangeable components that any watchmaker could replace, which turned the whole Swiss watch industry, not just Omega, into a force. In 2019, Omega celebrated 125 years since this breakthrough with De Ville Trésor 125th Anniversary Edition run by 19-Ligne.

De Ville Trésor 125th Anniversary Edition

De Ville Trésor 125th Anniversary Edition

In the meantime, Omega became a well-respected brand, especially among military forces due to their watches’ robust manufacture, which gave them wind in the back to push things further. Among new calibers produced in-house and by other manufacturers, the caliber 321 stands out. Developed in 1946, it was a breakthrough chronograph movement operating on the frequency of 18000 bph, with 17 jewels and astonishing power reserves for the time - 44 hours. The 321 chronograph uses a column wheel and features a 60-second register, a 30-minute and a 12-hour counter. So yes, super-smooth for its era.

In 1947, Omega made its first tourbillon movement called 30l. Only 12 pieces have been made for observatory trials and were nicknamed “Omega Observatory Tourbillons”. The breakthrough in the world of watchmaking lay in the fact that Omega tourbillon cages rotated once per seven and a half minutes, while others’ brands' tourbillons’ cages rotated once per minute. As expected by its makers, one of the Omega Observatory Tourbillons made it to the world record book in 1949. In 1950, another Omega tourbillon broke that record.

4-1947-omega-tourbillon-prototype1947 Omega Tourbillon Prototype

Then we have Omega caliber 1861 released in 1996. It is a hand-wound chronograph that operates on the frequency of 21600 bph and has 18 jewels. It is based on the Omega cal. 861 (Lemania 1873) that was released in 1968 and operates on 28800 bph. The cal. 861 had 17 jewels until 1992 and 18 jewels after, the same as cal. 1861. The cal. 1861 is basically a rhodium-plated version of cal. 861. Omega rates the accuracy of this caliber as -1/+11 seconds per day, but that is without the active chronograph function. The most famous watch run by this caliber is the Omega Speedmaster Moonwatch Professional.

5-1999-george-daniels-inventor-of-the-co-axial-escapementThe Coaxial escapement is invented by Dr. George Daniels in 1976

In 1999, the first Co-Axial movement was introduced, based on the invention of the Englishman George Daniels in the 1970s. The caliber 2500, as it was called, included the so-called Co-Axial escapement and 39 jewels. The cal. 2500 was the first commercial caliber with the Co-Axial escapement that had virtually no lubrication and used radial instead of sliding friction, which eliminated the issues with the traditional lever escapement. The results were greater accuracy over time and longer service intervals. The cal. 2500 is actually chronometer caliber whose accuracy is within the COSC limits: -4/+6 seconds per day. It features a small second hand and has a power reserve indicator, where its power reserve is rated at 48 hours. The caliber’s diameter is 25.6mm and the display features hours, minutes, seconds, and a date. The Caliber 2500 was originally made to beat at 28800 bph but was later reduced to 25200 bph, in order to prolong the maintenance cycle. Starting with 2007, Omega revealed another two Co-Axial calibers, 8500 and 8501 (25,200 bph and 39 jewels).

The movement 8500 is another honorable mention, widely used in the Seamaster collection. Basically, the cal. 8500 is the upgraded version of cal. 2500, being its more precise and more durable brother. It features a bi-directional rotor, which shortens the winding time. Starting with 2011, all watches featuring the cal. 8500 have an additional Si14 balance spring that adds stability in the hectic environment. We also have to mention the no-date, decorated version of cal. 8500, which is named caliber 8400. But this cousin isn’t just the beautiful one on the family, but also features power reserves of 60 hours and is resistant to magnetic fields up to 15,000 Gauss. The movement also uses Omega’s NivaShoc anti-shock system.

7-2008-omega-si14-balance-springOmega Si14 Balance Spring

While we’re at antimagnetic resistance, in 2013, Omega created the movement resistant to magnetic fields greater than 1.5 Tesla / 15,000 Gauss, which was not only significantly better than any previous caliber but also broke the world record. Something similar was used in Daniel Craig’s James Bond, but that one was labeled to the resistance of 15,007 Gauss in honor of the fictional agent’s codename. By utilizing non-ferrous materials, Omega eliminated the need for the soft-iron Faraday cage used by then, removing the necessity of de-magnetizing procedures of the case. This brought the idea of Master Chronometer Certification which confirms that, along with the COSC certificate by the Official Swiss Chronometer Institute, a movement has also passed a series of tests by METAS, the Federal Institute of Metrology.

Simply said, the Master Chronometers have an accuracy of 0/+5 seconds per day, power reserves of at least 60 hours, water-resistance of at least 100 meters and are resistant to magnetic fields of 1.5 Tesla. The first watch to receive the Master Chronometer Certification was the famous Globemaster, from the Omega Constellation collection Nowadays, the Master Chronometer Certificate represents the Swiss industry's highest standard of chronometric performance.


With all its breakthroughs so far, it is hard to know where Omega is headed in the future, but we can sure it will be big. From what we know so far, the cal. 8500 was eventually replaced with the newer version an automatic Co-Axial movement labeled 8900, which was launched at Baselworld in 2015. The cal. 8900 created a whole new family of movements, all being Master Chronometers, aka the most perfect timepieces on the globe. This new family of calibers is featured in watches such are Omega Globemaster, Omega Seamaster Planet Ocean models, etc.


References for all three articles:


Written by M.H. , images from OMEGA

Continue to read the Omega calibers – The super-powers behind the Omega watch faces

  • Part 1 - The comprehensive list of Omega calibers, sorted
  • Part 2 - Modern Omega Movements
  • Part 3 - Legendary Omega calibers

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