The Speedmaster Reduced (also called Speedmaster Automatic) is an automatic chronograph by Omega.

Designed to be a less-expensive, smaller, automatic version of the Omega classic Speedmaster Professional ("Moon Watch"), the Speedmaster Reduced has gained fans thanks to the smaller size and different dial. In contrast to the original Speedmaster, it has an automatic movement with wider-spaced subdials and Arabic numerals on the dial. Because the movement is (traditionally) modular, the Speedmaster Reduced is thicker than the original Speedmaster Professional, however, and sits higher on the wrist. The smaller case is waterproof to 3 atm.

Most Speedmaster Reduced models used modular movements (Cal. 1140, 1143, and 3220), pairing an ETA base with a chronograph module by Dubois-Depraz. These have “uneven” pushers and crown and subdials at 3, 6, and 9 and have various reference numbers, notably 3510. However, the 39 mm Speedmaster Automatic, introduced in 1991, uses the integrated Valjoux 7750-based Cal. 1155 movement, giving it a distinctly different look with subdials at 12, 6, and 9. The Valjoux-powered Speedmaster Reduced (Ref. 3520) is also sometimes known as the Mk40 or Triple Date (“TDate”) because it features a full calendar.

Omega has variously referred to the 39 mm Speedmaster as “Reduced” and “Automatic” since the 1988 introduction. The same case has often had different names The original 175.0032 was sold as the “Speedmaster Reduced” with Cal. 1140 in 1988, “Speedmaster Automatic Racing” with Cal. 1141 in 1996, and simply “Speedmaster Automatic” with Cal. 1143 in 1998. Similarly, the Valjoux-powered 175.0043 was sold as a “Speedmaster Reduced” in 1991 and just “Speedmaster Automatic” two years later. And the model numbers have remained consistent even as calibre numbers have changed Ref. 3510 used Cal. 1140 in 1988, switched to Cal. 1141 in 1996, Cal. 1143 in 1997, and finally Cal. 3220 in 2003. Although all four calibres are technically related and very similar, this has caused much confusion among modern collectors.

Note that one of the rarest and most sought-after Speedmaster models, case number 376.0822 from 1987, used the same 3510 reference number as common Speedmaster Reduced watches, even though it was a full-sized Speedmaster with a Lemania 5100 movement.

• 1988 175.0032 - Cal. 1140, “Speedmaster Automatic Reduced” 39 mm case, leather strap
  • 1988 175.0033 - Cal. 1140, “Speedmaster Automatic Reduced” 39 mm case, leather strap
  • 1988 375.0032 - Cal. 1140, “Speedmaster Automatic Reduced” 39 mm case, bracelet
    • 1989 375.0033 - Cal. 1140, “Speedmaster Automatic Reduced” 39 mm case, two-tone bracelet
  • 1988 475.0032 - Cal. 1140, “Speedmaster Automatic Reduced” 39 mm case, gold and diamonds, gold bracelet
• 1991 175.0043 - Cal. 1155, “Speedmaster Automatic Reduced Date” 39 mm case, leather strap
  • 1991 375.0043 - Cal. 1155, “Speedmaster Automatic Reduced Date” 39 mm case, bracelet
  • 1992 175.0063 - Cal. 1155, “Speedmaster Automatic Reduced Date” 39 mm case, leather strap
    • 1992 375.0063 - Cal. 1155, “Speedmaster Automatic Reduced Date” 39 mm case, bracelet
• 1999 175.0039 - Cal. 1143, “Speedmaster Automatic Reduced AC Milan” 39 mm case, leather strap
• 2000 275.0032 - Cal. 3220, “Speedmaster Automatic Reduced Ladies”
  • 2003 175.0041 - Cal. 3220A, “Speedmaster Automatic Reduced Ladies Japan”
  • 2003 275.0032 - Cal. 3220A1, “Speedmaster Automatic Chronometer Reduced Ladies”
• 2000 175.0040 - Cal. 3220, “Speedmaster Automatic Racing”
• 2001 175.0032 - Cal. 3220, “Speedmaster Automatic Reduced” (decorated calibre)
  • 2003 175.0032 - Cal. 3220A, “Speedmaster Automatic Reduced Japan”

• Omega-Uhren. Kaleidoskop einer bekannten Swiss Marke; Author Anton Kreuzer; ISBN 3853783546
• Omega-Modelle; Author Anton Kreuzer; ISBN 3853784186
• Omega Sportuhren; ISBN 3871880817
• Das ZEITGEFÜHL-Uhrenbuch; Author Gerd-Lothar Reschke; ISBN 3-938607-61-0