The Reason

The Running Equation of Time function is rarely executed in watchmaking. Here it is combined with a perpetual calendar, moonphases indication and entirely hand engraved automatic calibre.

Functions; running equation of time, moonphases, perpetual calendar and 24 hour indication.

Material Platinum   Case thickness 11.50mm   Case diameter 42.00mm   Water resistance 3.00 bar (approximately 30 meters)   Between shoulders 23.00mm    Sapphire crystals front and back with anti-reflective coating

The equation of time shows the difference in the hour of a day between “solar time” and  “civil time”. Civil time assumes that a day has exactly 24 hours and is constant during the year. Solar time is calculated based upon the real length of a day (the number of hours that pass between the time when the sun is in a given position in the sky and when it is in that same position the following day, which alters during the course of the year. )

Recto-verso of the case back.

The case back removed showing the full five correctors, movement and movement ring.

Calibre 3863

Winding automatic   Calibre thickness 5.25mm   Calibre diameter 26.80mm   Power reserve 72 hours    Jewels 39    Components 397    Frequency 4 Hz / 28'800 A/h

Rotor removed showing the fully engraved bridges. 

Base movement in various stages of dismantling.

The Nickel Phosphore treatment on the sliding pinion is a new technique which increases its hardness and durability. The setting mechanism traditionally receives more wear than most other parts of the calibre due to the manipulation it experiences directly from the users adjustment of the watch.

Partial explosion of the 3863 movement, excluding module.

The perpetual calendar and equation module, shown once the dial is removed.

Underside of the module.

A selection of the principle wheels and cams from the module.

Summary

A congruently thought through and executed complicated timepiece, containing the applications of a QP with the equation of time and the aesthetic elements reinforcing those functions in an artisanal engraved execution, stylistcally following the theme of the watch.

A partial exploded view of the module.

Diverse views of the assembled watch.

To learn more about this Villeret model please click on the Lettres du Brassus and view edition 9 where you can find an in-depth analysis on the watch and the subject of the equation of time.

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