De Bethune DB25 Starry Varius Chronomètre Tourbillon

Gravity is one of the greatest enemies of mechanical watches. Based on the tourbillon that AbrahamLouis Breguet invented for his 18th century pocket watches, De Bethune has sought to optimise it on today’s wristwatches.

To be more efficient on a wrist engaged in rapid and disordered movements, the tourbillon must have the highest possible frequency and fastest rotation speed.

In creating a titanium and silicon tourbillon with a frequency of 36,000 vibrations/hour, an extraordinarily light carriage (0.18 grams, the lightest ever created in the industry) spinning on its axis every 30 seconds, comprising a total of 63 components (the lightest of which weighs less than 0.0001 grams), this feat is easier to describe than to achieve.

The 42mm-diameter watch is equipped with the mechanical manual-winding DB2109V4 calibre, entirely designed, developed and produced within the De Bethune workshops in L’Auberson, Switzerland. A jumping seconds display ensures precise read-off. The state-of-the-art titanium balance-wheel with white gold inserts has been optimised for temperature changes and air penetration, regulated by means of the De Bethune balance-spring with its patented flat terminal curve which maintains a perfect centre of gravity.

The test report on the watch, measured in six positions, indicates the excellent results achieved by the model, with 0.00 sec. /day in all positions. This confirms that combining the jumping seconds complication with the tourbillon has in no way been detrimental to the precision of this chronometer.

Finally, the famous De Bethune starry sky with its gold-studded blued titanium dial can be personalised in accordance with the customer’s wishes (with a date and a geographical location). The traditional gold leaf method has been complemented by laser beam micro-milling to create a Milky Way effect.

Technical details

Name: DB25 Starry Varius Chronomètre Tourbillon
Reference: DB25STTIS3

Functions
Hours, Minutes, jumping seconds, 30’’ indicator via the ultra-light De Bethune tourbillon cage on case back

Movement
DB2109V4
Type: Mechanical manual-winding calibre
Adjustment: Winding and setting the time by means of the crown (2 positions)
Number of parts: 260
Jewelling: 43 jewels
Diameter: 30 mm
Power reserve: 4 days, ensured by a self-regulating twin barrel – De Bethune Innovation (2004)
Specificities:
– Titanium balance wheel with white gold inserts, optimised for temperature differences and air penetration – De Bethune Patent (2016)
– “De Bethune” balance-spring with flat terminal curve – De Bethune Patent (2006)
– Silicon escape wheel
– Ultra-light De Bethune 30’’ tourbillon in titanium – De Bethune Innovation (2008)
– De Bethune Dead Beat Second – De Bethune Innovation (2011)
Frequency: 36,000 vibrations per hour
Adornment: Silver plate and barrel bridge cover polished
Hand-snailed barrels
Hand-polished, chamfered steel parts

Display
Display: Hands in hand-polished steel

Dial
De Bethune star-studded sky in blued and polished titanium with hand-fitted white gold pins depicting the stars
Milky Way patterns produced by laser beam micro milling, gilded with 24-carat gold leaf
Silver-toned hours and minutes ring

Case
Case material: Polished grade 5 titanium
Case diameter: 42 mm
Case thickness: 10, 3 mm
Lugs: Integrated, hollowed lugs
Crystal: In sapphire crystal (1800 Vickers hardness) with double anti-reflective coating
Case back: Open back, De Bethune 30 ” silicon/titanium Tourbillon, 36,000 vph – central jumping seconds
Sapphire crystal (1800 Vickers hardness) with double anti-reflective coating
Water-resistance: 3 ATM

Strap
Extra-supple alligator leather, alligator lining
Buckle: Pin buckle in grade 5 titanium