Omega
speedmaster seventies "big s" vintage series - Calibre C.861 Guilt

vintage Speedmaster watch, Omega chronograph Moonwatch 145.22 manufactured in October 1977 according to its serial number (engraved on the calibre 861 movement). A collector's watch in excellent condition with a tropical gilt dial, naturally patinated from long exposure to sunlight. Screw-down 42 mm caseback in perfect condition with original engravings. Manual-winding mechanical movement, small seconds chronograph with Stop and Go function. Large central seconds hand, fixed tachymeter bezel surrounding Plexiglas crystal.

Vintage Omega Speedmaster chronograph marketed during the final years of NASA’s Apollo program, featuring a 42 mm steel screw-down caseback with inscriptions. Manual-winding mechanical movement, Omega calibre C 861, small seconds chronograph with Stop and Go function. Tropical gilt black tritium dial, flat second, and hour and minute hands in Type C2 Baton Tritium. Fixed tachymeter bezel Type B5-70-Style 1, surrounding Hesalite glass category A (Plexiglas). The three totalizer sub-dials for hours, minutes, and seconds are arranged for optimal time readability. The “S” in Speedmaster is the elongated style.

This pilot chronograph, powered by an 18-jewel movement operating at 21,600 vibrations per hour, offers the Speedmaster significant power reserve, delivering up to 40 hours of autonomy after a full wind. Based on the Lemania 1873 calibre—renowned for its reliability and tolerance to extreme temperatures—it is also praised for its shock resistance. It's worth noting that the characteristics of the Lemania 1873 led many prestigious brands to use it as a base for their own flagship models: TAG Heuer, Eberhard & Co., and even Breitling, for its Navitimer, all used this movement as a starting point. Finally, for comparison in the field of astronaut-grade watches, the Breitling 12 calibre powering the Navitimer Cosmonaute with 24-hour display, is based on the Lemania 1877—a close relative of the 1873—with the hour hand rotation speed halved. There’s no room for chance in space…

You’ll find an article retracing the history of the Speedmaster by following this link and an article on the history of Omega and its record-breaking watches on our "Watch Stories" page. The Speedmaster chronograph is a versatile timepiece—aviation, motorsports—whose features, heritage, and vintage chic aesthetic earned it massive popularity. Frequently spotted on the wrists of 1970s icons like singer Dalida or Jacques Brel, this legendary watch also made appearances in numerous films.

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