The 1990s were an especially creative period for Audemars Piguet, with the manufacture producing a number of unconventional watches that today sit somewhat in the shadow of the Royal Oak. Few capture that era better than the Star Wheel, a watch that revived the centuries-old wandering hours display and presented it in an entirely new form.
Introduced in 1991, the Star Wheel was inspired by wandering hour clocks dating back to 17th-century Rome. Rather than displaying the time through conventional hands, Audemars Piguet developed a system of three transparent sapphire discs, each carrying four hour numerals. These discs rotate around a central mechanism while simultaneously turning on their own axes. As the relevant hour travels across the upper portion of the dial, a pointer beneath it indicates the minutes along a 60-minute arc. Despite its mechanical complexity, reading the time becomes remarkably intuitive once understood.
The name Star Wheel comes directly from the mechanism itself. Beneath each of the three sapphire hour discs sits an eight-toothed, star-shaped wheel responsible for rotating the discs into the correct position as they travel around the dial. Rather than concealing this mechanism, Audemars Piguet placed much of it on full display, making the wandering hours mechanism the visual centrepiece of the watch.
This Ref. 25720BA is housed in a beautifully proportioned 36mm case crafted from 18k yellow gold. Its stepped bezel, short downturned lugs and relatively slim profile are characteristic of Audemars Piguet's classical watches from the period, providing an interesting contrast against the highly unconventional display.
More importantly, this particular example features the considerably less common engraved dial. The Ref. 25720BA was produced with both traditional guilloché and hand-engraved dial finishes, with the latter featuring an elaborate foliate pattern across the exposed gold surface. The engraving gives the watch a much more ornate character and provides a beautiful backdrop to the sapphire discs and exposed wandering hours mechanism.
Powering the Star Wheel is the automatic Calibre 2124, a 33-jewel movement modified to accommodate the wandering hours mechanism. Visible through the sapphire caseback, it is finished in the traditional Audemars Piguet manner and provides an interesting contrast to the much more expressive mechanics visible from the front.
The original Star Wheel remained in production for only a relatively short period during the 1990s, yet it has become one of the most recognisable examples of Audemars Piguet's creativity outside of the Royal Oak. The Ref. 25720BA is particularly compelling in this engraved configuration, combining a highly unusual wandering hours display with traditional hand-engraving and the restrained proportions of a classical 36mm yellow gold dress watch.
