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Heritage Models Calibre 321

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The Speedmaster Moonwatch 321 Stainless Steel

The legendary OMEGA Speedmaster is one of the world’s most iconic timepieces, having played a role in all six lunar missions. Powering this stainless steel model is the famous Calibre 321, the driving force behind the chronograph’s extraordinary space history.

The Speedmaster Moonwatch 321 Stainless Steel

Legend in steel

Inspired by the same 3rd generation style worn during America’s first spacewalk in 1965, this 39.7 mm model features a bezel ring in polished black ceramic [ZrO2], a tachymeter scale in white enamel; and a black step dial with Moonwatch hands and vintage OMEGA logo.
Watch details
Speedmaster Moonwatch 321 Stainless Steel

"As a further tribute to Speedmaster history, the Calibre 321 in steel includes the classic ‘Dot over 90’ on the bezel"

Speedmaster Moonwatch 321 Stainless Steel in action

Movement OMEGA Calibre 321

Calibre 321

The 321 is still highly sought-after by collectors around the world. As a tribute to its enduring popularity, OMEGA undertook extensive research and reconstruction in a dedicated workshop. Now, more than 50 years on from its last wave of production, the Calibre 321 has been reborn, in-line with its original specifications.

  • 55 hours Power reserve
  • Manual-winding
  • Frequency 2,5 Hz
Calibre 321

Recreating a Legend


Every Calibre 321 is created inside OMEGA’s Calibre 321 Workshop. This unique production space is dedicated entirely to the iconic movement, with all of the assembly steps being performed by the same watchmaker. The exacting process and attention to detail ensures that each new calibre is just as precise and legendary as the original.

"Ask most watch fans to name a famous movement they’d like to own and you’re bound to hear them mention the OMEGA Calibre 321"

Evolution of a movement

  • Original Calibre 321

    A descendent of the 27 CHRO C12, the enhanced chronograph movement, named in 1949, retained the intricate column-wheel feature popular with collectors. The 321 powered the Speedmasters qualified by NASA for use on all manned space missions and drove the chronographs worn by Apollo 11 astronauts.

  • Next step – Calibre 861

    Used between 1968 and 1997, the 861 had a number of modifications, including a flat balance-spring and the replacement of the column-wheel by a shuttle cam that offered even greater consistency. OMEGA also raised the frequency to 21,600 v/h to improve precision.

  • Rhodium-plated 1861

    The natural evolution of the 861 used in many Moonwatch models, the Calibre 1861, made with rhodium plating for greater stability, retained the 861’s frequency and the same shuttle cam and Delrin® chronograph brake designed to preserve the teeth of the chronograph seconds wheel.

  • The 3861 Master Chronometer

    It took 4 years to produce a calibre that could perfectly match the dimensions of the 1861 and achieve Master Chronometer certification. Released in 2019, the 3861 improved on power reserve, performance and magnetic resistance and included OMEGA’s revolutionary Co-Axial escapement and silicon Si14 balance spring.

  • The reborn Calibre 321

    OMEGA worked for over two years and in total secrecy to bring the movement to life. Using the 2nd generation Calibre 321 as a reference, the expert team’s extensive historical research included the use of “tomography” (digital scanning) to see inside the Speedmaster worn by astronaut Eugene “Gene” Cernan during the Apollo 17 mission.

The steel 321 up close

Our brief history of the 321 provides a compelling back-story of the Moonwatch and its famous movement. Find out what makes this particular stainless steel version a legend in its own right.
watch details

The 321 premieres in platinum

Discover the first watch powered by OMEGA’s reborn 321. Crafted from a special platinum alloy with the use of gold (Pt950Au20), it features a black ceramic [ZrO2] bezel and tachymeter scale in white enamel.

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The 321 premieres in platinum