We are huge admirers of Robert Gruebel and Stephen Forsey whose quest to push the boundaries of watchmaking continues to astound us. Their latest invention, the Perpetual Calendar with Equation of Time, is extraordinary.

Greubel Forsey has created ‘a mechanical computer’, that manages all the changes in the displays. The dial side predominantly shows the 24 hours of the day and night, the day of the week, the large date, the month, the hours and the minutes; the movement side shows the equation of time and the seasons and the year.

QP à Équation: Time Reinterpreted

This reinvention of the perpetual calendar integrates the Equation of Time into the perpetual calendar, as well as bringing practical new functions and indications that improve clarity. The priority was to simplify a complete perpetual calendar display and yet make it much easier to set by simply using the bi-directional crown.

QP à Équation

To meet this technical challenge Greubel Forsey invented a sophisticated coding mechanism: the patented Mechanical Computer. A stack of cams with movable fingers shift the indications on the dial and case back of the timepiece and the complete mechanism is fully integrated within the movement.

The timekeeping performance comes from Greubel Forsey’s third invention: the Tourbillon 24 Secondes, with its unique fast rotational speed and inclined angle to solve the problem of critical positions of the oscillator in relation to gravity. A 25° angle and the rapid revolution of the tourbillon cage significantly improve the chronometric performance of a system containing only one tourbillon, especially in stable positions.

For more information please visit https://www.greubelforsey.com

Technical Specifications:

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