Changing anything about the Moonwatch, therefore, runs the risk of producing in the Speedmaster faithful the same basic reaction you’d get if you moved a deer’s favorite salt lick. But change is exactly what has come to the Moonwatch. 

While it’s still near-impossible for anyone who’s not deeply immersed in the forensics of Speedmaster design details to tell the difference, well, consider me immersed. The new Speedmaster Moonwatch “Master Chronometer” is in my estimation a significant update both mechanically and cosmetically. 

In terms of externals, the changes are relatively minor (although they’re major signals to Speedmaster fans), and the biggest change is probably to the bracelet, rather than the watch itself. In fact, the new bracelet has probably gotten as much attention as the changes to the dial and bezel. The biggest change is under the hood, where we find a new movement: the co-axial caliber 3861, which is Master Chronometer certified, and which makes the Moonwatch a thoroughly modern member of Omega’s lineup of co-axial escapement watches.