View source for Patek Philippe Annual Calendar 5250

[[Patek Philippe]]'s [[2005]] '''Annual Calendar''' Ref. 5250 was one of the first wristwatches with a [[silicon]] [[escape wheel]] ever produced. It is the first member of their [[Patek Philippe Advanced Research|Advanced Research]] project.

==Overview==

In the 2000s, Patek Philippe set up an [[Patek Philippe Advanced Research|Advanced Research]] project to address the long-standing issues of [[isochronism]] and durability in watches. The main technology applied to this task was a proprietary alloy of [[silicon]] known as "[[Silinvar]]". The company proceeded steadily, producing first a Silinvar [[escape wheel]], then a [[hairspring]], an [[anchor]], and a [[balance]].

'''Ref. 5250''' was the first Advanced Research watch, introduced in [[2005]]. [[PP 315|Cal. 315 S IRM QUA LU SI]] included a Silinvar escape wheel, making it one of the first watches ever produced with such a component. The [[display caseback]] includes a large "[[cyclops]]" magnifier to allow the owner to inspect this high-technology component.

Although it used these high-tech components, Ref. 5250 was nevertheless a Patek Philippe. It included their revolutionary [[annual calendar]] mechanism with day and month subdials inset at 10:00 and 2:00, a date window below the [[moon phase indicator]] at 6:00, and a simple "+/-" [[power reserve indicator]] at 12:00. The dial features Arabic numerals at 3, 9, and 12, applied markers at all other hours but 6, and a "railroad" seconds track. The hour and minute hands are leaf shaped and feature [[lume]]. It has a traditional Patek Philippe case in [[white gold]], with long integrated lugs.

{{UD|
'''Reference:'''
:5250 white gold, 100 produced

'''Movement:'''
:[[Automatic]] [[manufacture]] movement: [[PP 315|Caliber 315 S IRM QUA LU SI]], 21,600 A/h
:[[Annual calendar]] module
:[[Silinvar]] [[escape wheel]] with Silinvar [[Spiromax]] [[balance spring]]
:[[Geneva Seal]]

'''Case:'''
:[[White gold]]
:D 39 mm
:[[Sapphire crystal]] caseback with magnifying bubble

'''Dial:'''
:Silver

'''Functions:'''
:Hours, minutes, [[central seconds]]
:[[Annual calendar]] with day, date, month
:[[Moon phase indicator]]

'''Limited edition:'''
:100 pieces
:Successor: [[Patek Philippe Annual Calendar 5350]]
}}

[[Category:Watch models]]
[[Category:Watches with annual calendar]]
[[Category:Patek Philippe models|Annual Calendar 5250]]
[[Category:Patek Philippe references|5250]]
[[Category:Patek Philippe Advanced Research models|5250]]