Omega 861

The Omega Caliber 861 is one of the most iconic and significant manual-wind chronograph movements ever made. Introduced in 1968 to replace the Caliber 321, it is Omega’s designation for the Lemania 1873 ebauche. The most critical change from its predecessor was the switch from a column-wheel chronograph mechanism to a more robust and cost-effective cam/shuttle system, along with an increased beat rate from 18,000 to 21,600 A/h for enhanced precision. The Caliber 861 became legendary as the heart of the Omega Speedmaster Professional “Moonwatch” (starting with ref. 145.022), famously passing NASA’s rigorous testing to be flight-qualified for all manned space missions. This copper-colored caliber powered the Speedmasters worn on every subsequent Apollo mission, including the moon landings, and throughout the Space Shuttle era. Its reliability and historical importance are immense, and it served as the base for numerous variants, including decorated versions (Cal. 863) and highly complicated models like the Flightmaster’s Cal. 910/911. It was succeeded by the rhodium-plated Cal. 1861 in 1996, ending a nearly 30-year production run.