A traditional perpetual calendar houses a highly complicated mechanism to display the basic time, calendar functions and leap year indication. The large number of displays makes the dial more complicated and some times less legible. Also it needs large number of components to construct the mechanical movement of a perpetual calendar watch.
He used only 9 additional parts to create the perpetual calendar function for this new timepiece. Less number of components and controls makes this watch more easy to use and high reliable. Traditional perpetual calendars need more laborious effort to set its functions. Most require a complex system of pushers, and the date cannot be adjusted backwards. Oechslin’s perpetual calendar can be set simply using the crown, and the date is adjustable both forwards and backwards.
Dial of Oechslin’s perpetual calendar watch features two central hands and 31 holes around the perimeter of the dial. It also features an inner disc with four holes and two small discs at 6’o clock and 12’o clock respectively.
- Date: The 30+1 holes around the perimeter of the dial display the date.
- Month: The 4 perforations in the month disk indicate the month. When the outermost perforation points to 1 o’clock, it is January. When the outermost perforation points to 2 o’clock, it is February. The month disk rotates clockwise.
- Leap year: The 4 perforations in the month disk also show whether it is a leap year or a common year. When the outermost dot is orange, it is a leap year (366 days). When it is dark, it is a common year (365 days). The leap year disk rotates clockwise beneath the month disk.
- Power reserve: The small circle beneath 12 o’clock is the power reserve indicator. Full power (60 hours) is when the dot is beneath the rightmost 12 o’clock marker. Empty is when the dot is beneath the leftmost 12 o’clock marker. The disk rotates counter clockwise.
- Hour and minute: The exact minute can be read using the date holes, which are spaced at 2 minute intervals. Holes mark even minutes and gaps odd minutes.
- Second: Just above the 6 o’clock marker is a seconds disk with a milled excentric dot. This disk shows the watch is running.
Model: Perpetual calendar
42mm grade 5 titanium case with screw-down crown
Dial, date disk, month disk, leap year wheel, seconds disk, power reserve indicator in gray patina
Markers in rhodium
Hour and minute hands in brushed platinum PT950
Date and leap year dots in orange
Waterproof sturgeon leather strap handmade in Switzerland
Ludwig's special buckle in Grade 5 titanium