The FirsT series
The first perpetual calendar wristwatch, however, was a one-off specimen. The first series-produced perpetual calendar timepiece from Patek Philippe was launched in 1941. This model, Ref. 1526, became particularly notable for setting the signature dial configurations used by later models, with two apertures showing the day and month in the upper half of the dial. The lower half, meanwhile, is dominated by the moon phase and date indicator on a sub-dial.
Powering the watch is the Caliber 12’’’-120 SC movement, which resides snugly in the 34mm yellow gold case. The minutes and hours hands are similarly in yellow gold, which contrasts nicely with the steel seconds hand and the silver dial.