Swiss gold dress watch with sapphire winding crown Circa 1980

Gold watch with moon phases, perpetual- and lunar calendar
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A Swiss thin 18K yellow gold keyless dress watch with a perpetual calendar, moon phases and lunar calendar, circa 1980. A polished and brushed case, stepped curved bezel, brushed band, hinged bow, cabochon sapphire set winding crown, and sapphire crystal. White enamel dial with painted radial Roman numerals, outer minute track, subsidiary dials for the months and 4-year cycle, days of the week and date, aperture for the moon phases with a lunar calendar. Blued steel pierced lozenge hands. A rhodium-plated movement, Geneva striping decoration, 20 jewels, straight-line lever escapement, monometallic balance adjusted to heat, cold, isochronism and five positions, self-compensating flat balance spring, shock absorber. Dial, case and movement signed.
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Thickness: 8 mm
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Diameter: 47 mm
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Signed: Audemars Piguet  Swiss
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The case is slightly scratched.