Breguet Classique Tourbillon Sidéral 7255 Design Insights

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The Breguet manufacture possesses a unique expertise in tourbillons, inherited since A.-L. Breguet obtained its patent on 7 Messidor Year 9 of the French Republican calendar – i.e., 26 June 1801. The House has never ceased to explore the infinite variations of this complication, but this is the first time it is presenting a “flying tourbillon” version. The Breguet Classique Tourbillon Sidéral 7255 also features a so called “mysterious” design, a construction that Breguet has mastered for many years.

Breguet Classique Tourbillon Sidéral 7255

Beyond honoring the master’s complication, this innovation also celebrates the very etymology of the word “tourbillon”. The choice of the term “Sidéral” is no accident: it evokes the world of stars, the precision of celestial movements, and the measurement of time by the heavens. It refers to astronomical time based not on the Sun but on the fixed positions of stars. It suggests a more rigorous, universe-oriented notion of time.

The presence of a tourbillon in a piece recalling Breguet’s astronomical developments also fits a historical context. Indeed, the contemporary meaning of “tourbillon” closely aligns with its etymology: “something rotating rapidly in a circle”. However, in the 17th and 18th centuries, things were different.

At that time, mathematician Blaise Pascal broadened the meaning of tourbillon to denote a “material system animated with rotational motion” (1647, Descartes, Principes Philosophiques). Since then, the notion of tourbillon has been extended to planetary systems, hence its direct link to astronomy.

Breguet is part of the scholarly tradition of his century. However, his invention was significantly ahead of its time, because 224 years later the tourbillon remains the subject of countless developments, without its principle ever truly being surpassed.

Variations on a tourbillon

A.-L. Breguet (1747-1823) imagined the tourbillon towards the end of the 18th century, while being careful not to set out its definitive technical aspects. As a perpetual inventor, driven by an unending desire to advance the science of watchmaking, he was aware that he had forged a principle, not a finite, immutable device.

He himself experimented with numerous forms, altering its design, oscillation frequency, speed of rotation or escapement (lever, detent or natural).

Breguet, which signed its watches “Breguet et fils” in the early 1800s, would itself devote more than thirty years to this project. Some forty tourbillons were produced between 1796 and 1829.

Today, by developing its first flying tourbillon, Manufacture Breguet is continuing in the spirit of the great watchmaker A.-L. Breguet by returning to the foundations of the tourbillon to offer a doubly different interpretation: flying and mysterious.

The flying tourbillon is a variant of the traditional tourbillon. Its purpose (to compensate for the effects of gravity on the balance wheel by rotating the cage that houses it) is therefore unchanged. However, it is a much later development: its first creations date back to the early 20th century.

Unlike the traditional tourbillon, the flying tourbillon’s cage is supported only by its lower bridge, without an upper bar. It is thus held solely from below. Elevated above everything, one is captivated by its mesmerizing display.

Its design and construction are more complex, however, since the tourbillon cage is no longer supported by a pivot at the top, only at its base. This means it must be more solidly constructed, better balanced and more finely adjustable than a normal tourbillon. Back in 1801 A.-L. Breguet strove for robustness and precision, more than 200 years later the manufacture that bears his name is still pursuing these objectives.

A mysterious design

Breguet has accentuated the suspended effect of its first flying tourbillon, by adding the mysterious complication.

The mysterious complication consists of imparting a movement to an organ without it being visibly linked to the rest of the movement. It is often used for watch and clock hands, but any rotating organ can be involved, including the tourbillon, as seen on the Classique Tourbillon Sidéral 7255.

The mysterious tourbillon is a striking complication which has been mastered by Breguet watchmakers. The lower bridge and the lower support of the tourbillon carriage, are, for this model, made of sapphire glass with an anti-reflective coating, rendering them invisible.

The point of contact between the gears and the carriage is not visible; it is offset from the tourbillon cutout and therefore hidden from view by the dial.

Mysterious and flying

The Classique 7255 thus incorporates both a mysterious and a flying tourbillon. This results from the combination of a regulator with an invisible drive that extends above the movement. Altogether, it creates a levitation effect and enhances visibility of the mechanism.

A tribute to astronomy

A.-L. Breguet, born in Neuchâtel on 10 January 1747, set up his own business in 1775. He opened his workshop on the Quai de l’Horloge on the Île de la Cité in Paris, his adopted home. In the world-famous French capital, the young Breguet studied at the Collège Mazarin with Abbé Marie, an eminent professor of mathematics. The two men would remain friends for decades, instilling in the future watchmaker a keen interest in astronomical studies.

The solid scientific background of his studies at the Collège Mazarin allowed Breguet to become an engineer ahead of his time. He would later join the Académie des Sciences (which was housed in the Collège Mazarin), as well as the Bureau des Longitudes in Paris, dedicated to perfecting various branches of astronomy.

During his lifetime, he worked with the astronomers Lalande, Biot, Bouvard, Nicollet and Cassini, as well as François Arago, a young astronomer he met at the Académie, to whom he delivered an eyepiece astronomical counter (a counter that attached to an observation telescope).

Astronomical aesthetics

With the new Classique Tourbillon Sidéral 7255 Breguet has, for the first time in its history, chosen to create a dial with aventurine enamel. A tribute to astronomy and the observation of the starry sky, its deep blue is punctuated with sparkling inclusions, shining like the stars that adorn the celestial vault.

The art of aventurine dates back to the early 17th century and has been constantly perfected ever since. For this model, Breguet chose to work it like grand feu enamel.

The glass must therefore be reduced to powder. The final compound must be finely calibrated – aventurine powder, for a perfect result, must have slightly larger grains than traditional enamel powder.

At least five layers of aventurine are necessary to make this dial, each layer must be fired in a kiln at over 800 degrees Celsius. And each firing is highly sensitive and requires great precision: firing for too long, or at too high a temperature, can result in the dial being permanently compromised.

The dial of the Classique Tourbillon Sidéral 7255 combines the best of both worlds: the deep, solid blue of the enamelled glass, and the sparkling randomness of the copper particles that represent the stars.

Given that each aventurine enamel dial is hand-crafted no two will ever be same, as such, all 50 examples of the Classique Tourbillon Sidéral 7255 are essentially unique pieces.

Technical explanation of the tourbillon

The Manufacture Breguet has paid particular attention to the tourbillon in the Classique Tourbillon Sidéral 7255 in order to perpetuate the relevance of this precious invention with contemporary aesthetic and technical design codes.

It is raised to accentuate the depth of the device and the sensation of floating in the void – a metaphor for celestial bodies floating in the immensity of space.

The tourbillon has been raised so that it protrudes 2.2 mm above the plate, and 0.9 mm above the aventurine enamel dial. The whole device has a total height of 7 mm. In other words, it is the tourbillon alone that gives the calibre its overall height and equally determines the thickness of the case (10.2 mm). In the Classique Tourbillon Sidéral 7255, the tourbillon is king: the entire movement is built around it, and its proportions guide those of the watch as a whole.

To achieve this majestic effect, it was necessary to invent a new way of designing and creating the dial. It is comprised of different elements such as a gold base with a raised rim and a gold tourbillon bezel. Such a design means that these elements have a secret technical function: They form raised walls of metal that close off the edges of the dial. These allow the aventurine enamel to be carefully built up throughout the enamelling process.

With the hour-marker, “Breguet” and “Tourbillon” appliques and the hour applied elements all gleaming with the warm glow of Breguet gold, the dial is not only a delight to behold but plays its own part in the “mysterious” complication. Hidden behind it lies the mechanism that drives the tourbillon cage, giving the impression that the cage is floating, with no visible connection to the rest of the movement.

The Tourbillon Sidéral, decoration

The Classique Tourbillon Sidéral 7255 is crafted in Breguet gold. This proprietary alloy was unveiled during the first chapter of the 250th anniversary celebrations. Its warm, subtly pink hue is inspired by the gold used by 18th century watchmakers, including Breguet. It is composed of 75% gold, enriched with silver, copper and palladium. Beyond its brilliance, it is distinguished by its resistance to discolouration and its stability over time.

For the first time, the recently unveiled Quai de l’Horloge guilloché is executed not only in a circular pattern on the case back and tourbillon support, but also in a linear fashion across the entire movement main plate.

This guilloche motif’s design is inspired by the delicate curves of the river Seine as it flows around the Île de la Cité and the Île Saint-Louis.

On the dial side, each piece is adorned with the brand’s secret signatures, complementing the many other traditional Breguet design codes such as the finely fluted case middle, the straight lugs and the Breguet “hollowed apple” hands. On the back, each piece is individually numbered from 1/50 to 50/50.