Patek Philippe CALIBER 324 S QA LU 24H/303, Manual

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Introduced in 1996 and patented by Patek Philippe,
the Annual Calendar is the first timekeeping mech-
anism that automatically displays the month, the day
of the week, and the correct date under considera-
tion of months with 30 and 31 days, so it only has
to be adjusted once a year on March 1. Its construc-
tion represented a formidable challenge. To eliminate
rockers and levers to the greatest possible extent,
Patek Philippe’s engineers designed an architecture
that relies mostly on wheels and pinions. The caliber
324 S QA LU 24H movement consists of 347 parts,
whereas a conventional perpetual calendar with a
moon-phase display needs only around 280 compo-
nents. The calendar indications are complemented
by a 24-hour dial. Additionally, the Annual Calendar
models feature an extremely accurate moon-phase
display that deviates from the true lunar cycle by only
one day every 122 years.