Calibre 1040 (and the similar Calibre 1041) is an Omega version of the Lemania 1341 automatic chronograph movement.

Omega and Lemania jointly developed an automatic chronograph movement for introduction in 1972. Cal. 1040 would power the new Omega Speedmaster Mark III, a range of models with modern tonneau cases to succeed the Speedmaster Professional Mark II. The Mark III was produced with three different cases, eventually gaining the Speedmaster Professional moniker. It would also power the Speedmaster Professional Mark IV, introduced in 1974.

Cal. 1040 has an unusual arrangement of hands and subdials. It is a 2-register movement, with 4 central hands and subdials at 6 and 9 on the dial

• Center hour and minute hands, chronograph seconds, and 60 minute chronograph totaliser
• 12-hour totaliser at 6 00
• Small seconds and 24-hour day/night disc at 9 00
• Date window at 3 00

Cal. 1040 was generally replaced by Cal. 1045, Omega's version of the Lemania 5100, after 1974.

The similar Cal. 1041 was a chronometer-grade version of Cal. 1040 and was used in the Omega Speedmaster 125th Anniversary Chronograph in 1973.

• Diameter 13 3/4 ligne
• Height 8 mm