This Heuer Moon Phase Day/Date wristwatch, powered by the base ETA 1100 movement with the moon/daydate/month module, recently came in for a full service. As with many modular calendar chronographs, the moonphase/date mechanism required extra attention. The intricate design of the calendar module—featuring day, date, and moonphase indications—required some fine adjustment to ensure proper functionality. After a complete disassembly and cleaning, the movement was carefully lubricated and regulated for accurate timekeeping. Once serviced, the watch ran beautifully, with all calendar functions advancing correctly.
The Heuer Moon Phase watch of the 1950s, powered by the ETA 1100 movement, stands out as an elegant example of mid-century Swiss horology. The ETA 1100 was a robust movement, enhanced with a calendar and moon phase complication. It offered a complete calendar—day, date, and month—along with a moon phase display. The moon phase, day and date function are automatic, while the month wheel was advanced manually. This manual wind movement featured a central sweep seconds hand and was known for its reliability despite the added complexity. During the 1950s, other brands such as Nave, Leonidas, and Zodiac also employed the ETA 1100 in their triple calendar moon phase watches, often housed in similarly styled gold or gold-plated cases. These watches were not only practical but highly decorative. Today, they remain sought-after pieces for collectors who appreciate mechanical artistry and mid-century design.
For more information on initiating the repair of your vintage watch see getting started, and additional information on Heuer servicing in general. Further reading: Choosing where to have your watch repaired.
