Audemars Piguet, Royal Oak Day-Date, Ref. 25594ST

SPECIFICATIONS  

Brand: Audemars Piguet
Model: Royal Oak Day-Date Moon Phase
Reference Number: 25594ST.00.0789ST.05
Movement: Automatic
Condition: Good 
Gender: Men’s
Time Period: 1990s
Box: Yes
Papers: No

THE CALIBER

Caliber: 2124/2825
Jewels: 33

THE CASE

Case Material: Stainless steel
Case Diameter: 36.5 mm
Thickness: 9 mm
Waterproof: 100 ft./ 30 m./ 3 ATM
Bezel Material: Fixed stainless steel secured with 8 white gold screws
Glass: Sapphire Crystal
Caseback: Solid
Dial: Cream with waffle “Grande Tapisserie” decoration
Dial Numerals: 18K yellow gold applied with luminescent coating faceted baton hour indices

THE BRACELET / STRAP

Bracelet Material: 18K yellow gold and stainless steel
Buckle: Fold-over Audemars Piguet
Buckle Material: Stainless steel

THE FUNCTIONS

Hours, minutes, subsidiary day of the week dial at 9 o’clock, subsidiary date of the month dial at 3 o’clock, moon phase indicator at 6 o’clock, 45-hour power reserve

FURTHER READING

Octagon-shaped case designed by Gerald Genta
18K white gold applied and luminescent coating Royal Oak hour/minute hands, white gold stick-shaped sub-dial hands
Stainless steel solid case back secured with eight white gold screws
Stainless steel screw-down hexagonal crown
The three-body case, lugs, and flat bezel are polished/brushed.
Integral stainless steel link bracelet with a stainless steel deployant buckle and downturned integral stainless steel lugs.
This Audemars Piguet Royal Oak ref. 25594 ST has a mechanical automatic Audemars Piguet caliber 2124 movement rhodium-plated, with fausses cue embellishment. The rotor is mounted on a ball bearing, with a peripheral mass in 22K gold. It has a round shape, 26mm diameter, thickness of 4.55 mm. It is constructed with a smooth balance in Glucydur, 33 rubies (escapement wheel with end stone), a flat balance-spring in Nivarox 1 with an adjustment device with a micrometric screw, Kif anti-shock. The plate is perlage decorated, the bridge and rotor are Vagues de Genève decorated, and Anglage finished, the screw heads are mirror-polished.
This ref. 25594 SA powered by the self-winding caliber 2124/2825 was introduced around 1984. The 2825 moon phase and day date modifiers are put on the base 2124 auto with date window movement, a JLC base caliber fine finished and adjusted at AP.
The screw-down crown controls ALL functions – day, date, moon phase, and of course, the hour and minutes.
Defining the crown positions as follows:
P0 = crown in, all the way
P1 = crown out first detente position
P2 = crown out second detente position, or all the way out
P0 is a neutral position and (I believe) allows the automatic movement to be wound manually.
P1 = to set the moon phase. Turning the crown upward (toward 12) advances the moon phase without affecting other settings or functions.
P2 = in this position, the crown controls the hour and minute hands directly. Thus, at 12 am indicated, the date advances, and at 1:30 am, the day of the week advances. Thus, as one sets the time through its 24-hour cycle, the date advances every midnight, and the day of the week advances about an hour later.
This mechanism oscillates at the frequency of 21,600 vph (3 Hz).
Serial # D-85***  1992-1993
Case, dial, and movement are all signed.
Incomplete (box, no papers)