Omega · Moonwatch
3861
The hand-wound Co-Axial Master Chronometer calibre in the modern Speedmaster Moonwatch.
At a glance
- Type
- Hand-wound mechanical
- Display / complication
- Chronograph
- Architecture
- Manual winding, Co-Axial escapement, 3 Hz balance
- Timebase
- 21,600 vph / 3 Hz
- Power reserve
- 50 h
Reference sources reviewed 7 November 2026. Published specifications, not independent measurements. Versions and complete-watch specifications can differ; fields without a verified figure are omitted or identified.
Find it in a watch
Omega Speedmaster Moonwatch Professional with calibre 3861
An example from the linked references. Check the exact model and production generation.
What distinguishes it
Look beyond the reference.
Winding through the crown is part of the ownership routine; there is no automatic rotor to replenish the mainspring while worn. The chronograph measures elapsed time while the watch continues displaying ordinary time. Omega specifies a 3 Hz rhythm and a 50-hour reserve.
For the enthusiast
The Moonwatch name spans several movement generations. Check that the exact reference contains 3861 before assigning its specifications to an older Speedmaster. Compare the automatic 9900 to see how two modern Omega chronographs take different approaches to winding and construction.