861

About the Omega 861

Built on the Lemania 1873, it switched the chronograph with a cam and lever rather than a column wheel, which was cheaper to make and to service, and coupled it with a horizontal clutch; it beat at 21,600 vph with a 48-hour reserve at 27 mm across, with 17 jewels until 1992 and 18 after. The ref 145.022 that carried it from 1969 flew on the later Apollo missions, and the 1861 of 1997 is the same movement with a rhodium-plated finish. The chronograph piece explains the cam-and-clutch family it belongs to.

In the library it powers 14 Speedmaster Moonwatch references, the Alaska III and the Apollo editions among them, and one De Ville. 7 are limited editions.

The 321 is the Lemania 2310-based movement it replaced, and the 3861 the co-axial Master Chronometer that ended the family in 2021.