Patek Philippe 5951 Mode D'emploi page 7

saVing a referenCe time
Actuate the pusher in the winding crown to
simultaneously start the chronograph and split-
seconds hands. To save a reference time, actuate
the pusher at 2 o'clock; the rattranpante hand will
stop at the reference time. Actuate the pusher
in the winding crown twice in succession to
stop and reset the chronograph hand. The split-
seconds hand will stay at the reference time.
From now on, you can use the pusher in the
winding crown as often as you wish to perform
measurements with the chronograph hand and
compare them with the reference time indicated
by the split-seconds hand. After completion of
the time measurements, actuate the pusher at 2
o'clock to cause the split-seconds hand to catch
up with the chronograph hand. Now, you can
reset both hands to zero with the pusher in the
winding crown.
Note: Thanks to their newly developed toothing profile, the
chronograph wheels of the Ref. 5951 are much more wear-
resistant than conventional wheels with triangular teeth.
However, you can further avoid unnecessary wear by using
the chronograph and split-seconds hands only for timing
events rather than keeping them running permanently.
perpetual Calendar
The perpetual calendar indicates the date, the day
of the week, and the month, automatically taking
into account months with 28, 29, 30, and 31 days: it
switches directly from September 30 to October 1 or,
in non-leap years, from February 28 to March 1. The
date, day, and month are complemented by a leap-
year indication and a moon-phase display, which is
so accurate that it deviates from the true lunar cycle
by only one day every 122 years. If the watch is wound
daily, the perpetual calendar will not require any
corrections before February 28, 2100; this is a secular
year that by exception omits the 29th of February.
Note: The date change mechanism is active between 10 pm and
2 am whereas the moon phase switches between 12 noon and 2
pm. During these time periods, adjustments of the calendar and
moon-phase indications with the correction push pieces should
be avoided. To assure that corrections will not interfere with the
operation of these mechanisms, first set your watch to 6 am;
observe the day/night indicator (white range). If your watch
has stopped running, do not make corrections or adjustments
before rewinding it with about 15 clockwise turns of the crown.
Correction push pieces should be actuated exclusively with the
correction stylus that was delivered with the watch. The use of
any other tool could damage your timepiece. The adjustments
must be performed in the order described below.