Omega Caliber 3861 Complete Guide

Omega caliber 3861

Omega Caliber 3861 Complete Guide

The Caliber 3861 was released by Omega for the new Apollo 11 watches in gold and steel, released in 2019 to mark the 50th anniversary of the Apollo 11 space mission.

The Caliber 3861 uses the Lemania 1873 as its base just like the standard Moonwatch with caliber 1861 and the previous caliber 861. As such, the caliber 3861 is technically, at its core, an 1861 movement, but with a number of changes made to it.

The Caliber 3861 is a hand-wound movement with 26 jewels which beats with a frequency of 21600. It has a chronograph function and displays Small Seconds, Hours, Minutes. It is a certified Master Chronometer, certified by METAS. The movement has a diameter of 37 mm and a thickness of 6.87 mm and offers a power reserve of 50 hours.

The movement is resistant to magnetic fields to 15,000 gauss.

Omega caliber 3861

In terms of technology, the movement has a free-sprung balance with silicon balance spring (Si14). Depending on if the movement is used in the full gold version or steel and gold version, it either has a gold plated finish or rhodium-plated finish. Regardless of this, the movement still has the same caliber number. Furthermore, the movement has a Co-Axial escapement. The bridges have been decorated with straight Geneva waves.


“Aesthetically, the latest movement is closer to 1861’s more beautiful cousin, the 1863, which featured gold engravings and Geneva waves. To match the case materials of the Apollo 11 tributes, two versions of the 3861 were produced: one with rhodium-plated bridges and main plate; and another in gold with a Moonshine gold-plated finish. The use of Moonshine gold-plated main plate and bridges marks another first for the pioneering brand. The innovative patent-pending material was introduced in 2019 to coincide with the lunar landing’s 50th anniversary”.


According to Omega, it took 4 years to develop the caliber 3861. The goal was to make a Master Chronometer Certified upgraded version of the 1861. This was, of course, a challenge as it meant that Omega would have to find space to fit its new technology, as mentioned above, into a caliber such as the 1861, which has been in production for more than two decades.

Lens Position: 2774

The result is that the 3861 has more than 240 components. All areas of this movement have been improved, most notably the power reserve, accuracy performance, and magnetic resistance. It has a power reserve of 50 hours. One technological improvement of the 3861 from the 1861 is that Omega introduced hacking seconds, allowing the seconds hand to stop when pulling out the crown for more accurate time-setting.

Omega caliber 3861

For this movement, Omega removed the frequency regulator as the lever has a risk of accidental frequency shifts. Instead, Omega uses four adjustable screws on the balance wheel for adjusting the movement.

What is interesting about this movement is that, regardless if it is the gold version or the steel version 3861, they have both been decorated to the same finish. This is unlike the caliber 1861 and 1863. The 1861 is used in Speedmasters with a closed case back, and therefore, it is not finished to the same level as the 1863, which is used in Speedmasters with a see-through case back. This is despite the fact that the Apollo 11 in steel has a closed case back.

Lens Position: 3988Omega caliber 3861

Speculations have circulated that omega would come to replace the now several-decade old 1861 and 1861 with this 3861 caliber which incorporates all the latest Omega technology. However, this is something that is yet to happen.

Omega Caliber 3861 Specifications

  • Jewels: 26
  • Frequency: 21600 BPH
  • Technology: Co-Axial escapement, resistant to magnetic fields to 15,000 gauss, hacking seconds, free-sprung balance with silicon balance spring (Si14).
  • Diameter: 37 mm
  • Power reserve: 50 hours
  • Height:6.87 mm
  • Base: Lemania 1873
  • Certification: METAS Master Chronometer
  • Parts: more than 240 components

Used in:

  • Omega Speedmaster Apollo 11 310.20.42.50.01.001 in steel and gold.
  • Omega Speedmaster Apollo 11 310.60.42.50.99.001 50 Anniversary Moonshine Gold 
  • Omega Speedmaster Moonwatch professional hesalite 2021 reference 310.30.42.50.01.001
  • Omega Speedmaster Moonwatch professional sapphire 2021 reference 310.30.42.50.01.002
  • Omega Speedmaster Moonwatch 2021 310.32.42.50.01.001
  • Omega Speedmaster Moonwatch 2021 310.32.42.50.01.002
  • Omega Speedmaster Moonwatch 2021 310.60.42.50.01.001
  • Omega Speedmaster Moonwatch 2021 310.63.42.50.01.001
  • Omega Speedmaster Moonwatch 2021 310.60.42.50.02.001
  • Omega Speedmaster Moonwatch 2021 310.63.42.50.02.001
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