30 minutes on the wrist - The Jaeger-LeCoultre Master Grande Tradition Grande Complication
If you look at the night sky from the Northern hemisphere, you will see it as it’s reproduced on the blue dial of the Jaeger-LeCoultre Master Grande Tradition Grande Complication . Moving from the Vasco da Gama to one of the five super complicated timepieces (I mean Tourbillons, Minute Repeaters or both) unveiled by the manufacture from Le Sentier at the last SIHH 2015 , has been quite natural.
This is the first time that Jaeger-LeCoultre adopts a rose gold case for its “astronomical” watch, that is capable of simultaneously displaying solar and sidereal hours.
This is a good chance for me to explain how it actually works (it is the only flying tourbillon ever made to display the sidereal hour). Inside a Jaeger-LeCoultre Master Grande Tradition Grande Complication the one minute flying tourbillon is also orbital, as it moves counterclockwise to display sidereal time. I guess master watchmakers at Jaeger-LeCoultre opted for a one minute tourbillon to reproduce the earth’s rotation along its axis, while its complete rotation, jointly with the blue dial and, as already mentioned, counter clockwise, is completed in 23 hours , 56 minutes and 4 seconds , a sidereal day’s duration, widely used by astronomers to avoid any problems connected with the earth orbiting around the sun.
A small gold sun placed peripherally on the dial, that rotates along a 24 hours ring , indicates whether it is day-time or night-time. On the blue dial for example the Great Bear , Cassiopeia and the twelve constellations from the zodiac are clearly visible. The “earth” is a masterpiece of micro-engineering: it is a flying tourbillon (thus only fixed on the movement side) made of 73 parts , 12,42mm wide and 3,85mm high . The tourbillon cage is made of titanium , it has a Breguet spring over-coil and its balance wheel , that vibrates at 4Hz , has 10 weight screws and 4 screws to fine-tune its inertia.
Jaeger-LeCoultre has also equipped its Master Grande Tradition Grande Complication with a minute repeater complication (and redesigned the lateral slider for enhanced ergonomics), thus allowing for a third, acoustic , indication of hours , quarters and minutes too. The manufacture opted for a chime that sounds as a cathedral gong, hence a tone that ensures a r esonance length far greater than that of a classic one. The quality of the cathedral gong is a terrain where the world’s best manufactures constantly compete with each other; Jaeger-LeCoultre optimized the gong by replacing the round shape with a square one , to enlarge the contact surface (by perhaps equalizing the force distribution). It also adopted trébuchet hammers , that you can see in this photo
a technical solution whose design is patent pending, and whose outcome is the improvement from nearly 30% to 80% of the energy transmission released from the spring to the hammer . This solution, along with a silicon escapement and ceramic ball bearings for the tourbillon cage, aims to minimize friction and to improve efficiency , one of the greatest challenges a watchmaker has to face while designing such a complicated timepiece.
The J aeger-LeCoultre Master Grande Tradition Grande Complication has a 45mm wide and 15,8mm thick case. The movement, caliber Jaeger-LeCoultre 945 has 527 parts and a 40 hours power reserve. I’ve read here and there some negative comments about this watch being a bit too thick; this, to be honest, makes me smile, when we take into account not only how complicated it is, but how on top of that it adds a revolving dial with a tourbillon, placed outside the movement. In this case the three-dimensional effect is done on purpose I believe, as it gives the watch that visual depth typical of the night sky. What I would try to do, however, is an accelerated video, just to reproduce, in a short time, the tourbillon rotation along a sidereal day, something that just a few lucky people will be able to enjoy, as it will retail for more than 350.000 €, approximately.
(Photo credit: Google; Horbiter's proprietary photo-shooting by Entropik )
Gaetano C. @Horbiter - Watches & Luxury