Blancpain creates a Limited Edition Le Brassus Marchante M.Y.S. featuring an evolution of its world record-breaking equation marchante movement. This Limited Edition is to mark the seventh anniversary of Blancpain’s partnership with the Monaco Yacht Show.



For two centuries, perhaps the rarest of watchmaking complications has been the equation of time. Measuring the difference between the length of the solar day, which constantly varies over the course of the year, and the length of the standard 24-hour civil day, an equation of time display has graced only the most exclusive watches and clocks. Even more refined and exclusive is the equation of time display that shows both solar time and civil time with two separate minute hands. In all of watchmaking history, only a handful of the most important clock and pocket watches have featured this form of dual time, termed ‘equation marchante’ or ‘running equation’ display. Indeed equation marchante timepieces have been so exclusive that nearly every single one produced over the last two hundred years has been catalogued and recorded as a historically significant piece.


This picture records the sun's position in the sky, each two weeks at the same time.

Blancpain startled the watchmaking world in 2004 when it revealed that it had succeeded in miniaturizing the running equation, which had previously only been built in large-scale clocks and pocket watches. At the Basel fair, Blancpain unveiled the first wristwatch in the world featuring a running equation of time, the Le Brassus Equation Marchante. This landmark timepiece was produced in a limited series of 50 pieces, which were all eagerly snapped up by passionate collectors. However to mark the seventh anniversary of Blancpain’s partnership with the Monaco Yacht Show, Blancpain has created a Limited Edition Le Brassus timepiece featuring an evolution of its world record-breaking equation marchante movement.

It is modern convenience that our timepieces measure and display an exact 24-hour day. Were we more tied to the ancient sundial, we would know that the length of the day changes considerably over the course of the year. The variability in the length of the solar day is the result of what some may consider two flaws in the earth’s position relative to the sun. First the orbit of the earth is not round, but in fact highly elliptical. Second, instead of rotating on an axis which is perpendicular to the plane of the orbit, the earth is inclined at an angle of 23 degrees. These two abnormalities combine to produce days, which consist of a single rotation of the earth relative to the sun, of slightly longer or shorter length depending on the time of the year. Ancient astronomers fascinated by the movement of heavenly bodies, most particularly the most important orb in the sky, the sun, centuries ago began recording data showing the changes in the length of the solar day throughout the course of a year. Their findings have been most commonly expressed by a complex oblong chart termed an analemma. The twin kidney shape of the analemma shows that on but four days a year (April 15th, June 14th, September 2nd and December 26th – these dates change with the leap years) 24-hour civil time and solar time have caught up with each other. At other times the differences between the two may be as much as -16 minutes and + 15 minutes.


The yearly rotation of the earth around the sun.

Mechanical marvels lie behind the realization of an equation of time display. Through precise calculations, watchmakers have developed a figure eight cam which mechanically mimics the analemma curve derived by astronomers. Turning once per year, this cam is used to drive a finger producing a plus minus display of the difference between solar time and civil time. Blancpain wished to go further however. Its watchmakers strove to create for the first time in a wristwatch an equation display that would simultaneously show both civil time and solar time on two separate minute hands. This was the Le Brassus Equation Marchante watch.

The first of the two minute hands indicates civil time in a conventional fashion. The second minute hand, adorned with the image of a golden sun, indicates solar time. The user can thus, directly read at a glance both civil time and solar time, as well as visualize the ever-changing relationship between the two.

Yet the simplicity of the appearance of the running equation display gives little hint of the complex horological movement that lies under the surface of the dial. The mechanism of the Equation Marchante has been integrated within a self-winding movement, itself combined with the world’s thinnest perpetual calendar module. In turn the equation mechanism is synchronized with the perpetual calendar. The great obstacle which Blancpain surmounted in the design of the running equation was finding a way to drive the solar hand from two sources, the regular running train of the watch, powering the civil minute hand, and a gear train driven by the precision figure eight shaped equation cam. The solution was found in an innovative system of differential gears. The solar hand is, thus, simultaneously powered by two separate sources, its position constantly effected by both. Because the solar time indication is constantly changing in real time, the term ‘running equation’ is the perfect description.

The Limited Edition Equation Marchante M.Y.S is derived from the 2004 watch. Adding to its refinement, the equation display in this new limited edition highlights the running solar hand by dispensing with a plus minus indication which was included on the original watch.

The Le Brassus Equation Marchante M.Y.S. is based upon Blancpain’s calibre 3863 and its 364 components. Endowed with a 72-hour power reserve, this mechanical self-winding movement displays, in addition to the running equation of time by two separate hands, indications of the date, day of the week, month, leap years and small seconds at 6 o’clock. The Equation Marchante thus focuses on essentials, ensures excellent legibility, and features a blend of inner complexity and apparent outward simplicity. In keeping with the same spirit, all the components of this mechanism are chamfered, polished, rhodium-plated, decorated and assembled by hand by Blancpain’s master-watchmakers.


Horological view of the yearly rotation of the earth around the sun, represented by the cam.

To celebrate this encounter between astronomy and haute horlogerie, a circular aperture at 6 o’clock on the dial allows one to gaze upon the equation cam, whose position portrays the universe in miniature. The small seconds hand also turns in the centre of this opening. The hand-sewn crocodile leather strap is fitted with a folding clasp in red gold.

Paying homage to the master watchmakers, designers and artisans who have contributed for the past 270 years to Blancpain’s acknowledged mastery of the watchmaking art, the Equation Marchante M.Y.S. is crafted in an exclusive limited series of seven pieces, each hand-engraved and personalized following the owner’s wishes.


Source: Blancpain

www.blancpain.com

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