Omega Speedmaster Caliber 3861: A Community Accuracy Test

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Dr No, a respected member of the WatchProSite community, initiated a fascinating experiment to assess the real-world accuracy of Omega's Caliber 3861 movement. This third-generation Professional movement, found in the Apollo 11 50th Anniversary Moonshine and steel/gold models, represents a significant update for Omega. Dr No's call for a community-wide, ten-day 'on-the-wrist' timing test aimed to gather empirical data from multiple owners, providing valuable insights into the performance of this important co-axial escapement.

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. . . would you be willing to participate in a ten-day 'on-the-wrist' timing test?

The reason I ask is because the cal 3861 represents a third-generation Professional movement that should in theory perform exceptionally well. There are enough owners in this community for a meaningful conclusion to be drawn.

Can all 2019 Apollo 11 owners reply in this thread? I realize most, if not all, of you wouldn't normally wear your Moonshine for ten straight days, but if you're all amenable, we'll be able to provide the entire Omega fan base with food for thought.

Cordially,

Art

About the Omega Ref. 3861

The Omega Speedmaster Moonwatch Professional, reference 3861, represents a significant evolution within the Speedmaster collection. This reference updates the core Moonwatch design while incorporating modern technical advancements, maintaining its established aesthetic. It is positioned as a contemporary iteration of a well-known chronograph, appealing to collectors who appreciate both heritage design and updated mechanical performance. The model is offered in various material configurations, providing options for different collector preferences.

This Speedmaster Moonwatch Professional features a 42 mm case, with a thickness of 13.18 mm. The case houses the Omega Co-Axial Master Chronometer Calibre 3861, a manual-winding movement. The crystal protecting the dial is available in hesalite or sapphire, depending on the specific sub-reference. The movement provides a power reserve of 50 hours, ensuring reliable operation over an extended period.

The reference 3861 appeals to collectors seeking a Speedmaster with enhanced precision and anti-magnetic properties, certified as a Master Chronometer. Its availability in materials such as stainless steel and Moonshine™ gold allows for diverse collecting strategies. The consistent case dimensions and movement across these variants underscore a unified design approach, while material choices offer distinct visual and tactile experiences.

Specifications

Caliber: Omega 3861

Case: Stainless Steel, Moonshine™ Gold

Diameter: 42 mm

Dial: Black

Water Resist.: 50 meters

Crystal: Hesalite or Sapphire

Key Points from the Discussion

The community test protocol involved fully winding the watch, setting it to an atomic clock, winding it daily at the same time, wearing it normally for ten days, and alternating overnight resting positions (dial up/dial down).
One participant reported a net gain of six seconds over the ten-day test, expressing high satisfaction with the accuracy of their Omega Speedmaster with the Caliber 3861 movement.
The Caliber 3861 showed a gain of one second over the first 24 hours and a total gain of two seconds over 120 hours, with observations suggesting positional influence (gain dial up, loss dial down).
The decision to update the Professional movement with a co-axial escapement, despite previous statements from Omega management, highlights a significant strategic shift likely driven by performance data.
A minor drawback noted for the Caliber 3861 was the crown's hardness for winding, which was described as a 'pain for the fingers' but expected to diminish with use.
Vintage Omega movements, such as the Genève chronometer Caliber 602, Caliber 420, and 30T2rg, can still achieve remarkable accuracy (e.g., a two-second loss over five days) when recently serviced and regulated, though their long-term stability compared to modern movements is a point of discussion.

The Discussion

Cpt Scarlet

Jan 30, 2020

It’s an interesting idea Art....

I just need to contemplate having it on my wrist for 10 days.

radone

Jan 30, 2020

Same here. I guess it is going to be hard.

MCG (Markus)

Jan 30, 2020

If 10 days is too much, 3 days is better than nothing... 👍🏻😅 [nt]

holdemchamp1225

Jan 30, 2020

hi Art, you could also include the members with the Apollo 11 50th Anniversary in SS as well since it also uses the 3861 caliber...

as for a 10 day on the wrist timing test, that is asking ALOT of me since I change watches daily and sometimes twice a day I could try and do a weekend or 3 days BUT 10 days is torture

raymond74

Jan 30, 2020

Unfortunately i don't own one,

but I was allowed to see, feel and handle it by one of our forum-menbers. What a magnificent piece! All the lucky owners out there, congrats!!!

MCG (Markus)

Jan 30, 2020

If 10 days is too much, 3 days is better than nothing... 👍🏻😅 [nt] [nt]

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Omega Speedmaster Caliber 3861: A Community Accuracy Test

About the Omega Ref. 3861

Specifications

Key Points from the Discussion

Continue the conversation

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