Patek Philippe 5207 Mode D'emploi page 3

Instantaneous perpetual calendar with aperture displays. Manually wound.
With an extraordinarily large number of parts,
549, to be precise, this timepiece ranks among
Patek Philippe's most complicated wristwatches.
The case flanks and the minute-repeater slide are
artistically hand-engraved. The slightly cambered
sapphire-crystal glass protects a "Honey Gold" 18K
dial that gives the perpetual calendar an exceptio-
nally unique face. The apertures for the day, date,
and month feature mirror-polished white-gold
frames and are arranged along an arc between 10
and 2 o'clock. The subsidiary seconds dial is posi-
tioned at 6 o'clock and accommodates the lunar
disk in the characteristic moon-phase cutout.
Each of these little discoveries by themselves
delight watch connoisseurs, but the big surprise
Reference 5207
Caliber R TO 27 PS QI
Wristwatch with minute repeater. Tourbillon.
Platinum.
comes at midnight, when all displays of the perpetual
calendar advance instantaneously and synchronously.
This is not merely a welcome function, it is also
an extremely challenging additional complication
based on the flawless interaction of 212 individual
parts. Patek Philippe's caliber engineers invested
five years in the development of this ingenious
mechanism to assure that the disks for the day,
the date, the month, and the leap-year cycle really
switch to the next calendar day simultaneously and
at the same time. The core of their invention is
a mechanism consisting of levers and complex
program cams for which two patent applications
were filed.