The essence of the watch lies in its interpretation of astronomical timekeeping for the wrist. And there could be no driving force more suited to this task than the pulsing heart of a flying tourbillon orbiting the dial, depicting a sky-chart of the northern hemisphere.

A sun performs a full revolution in 24 hours around the rim, thereby displaying a 24-hour indication, zodiac signs, as well as the days and months appearing on a circular scale surrounding the dial.
Its precision is based on advanced technology, with a flying tourbillon setting the pace within an ultra-light titanium cage.

Additionally, the watch incorporates a minute repeater in which the sound is generated by two crystal gongs directly fixed to the sapphire crystal.
Equipped with ‘trébuchet hammers’, the Grande Complication watch offers a sound of unprecedented clarity and fullness, at a simple push of the dedicated slide.

The gem-setting motif conceived by designers accentuates the distinctive architecture of the Master Grande Tradition case.
The crown is meticulously set with baguette-cut diamonds, while two rows of baguette-cut diamonds extend to the right and left of the crown to adorn the convex-shaped side of the case, and descend to the lugs.

Sky Chart & Zodiacal Calendar
Since the earth orbits around the sun as well as upon its own axis, the solar day is slightly longer than the sidereal day, differing by about one degree, meaning almost four minutes.
To underline these celestial ambitions that make the watch a perfect instrument for astronomical observations, the sky disc performs a rotation in 23 hours and 56 minutes, meaning one sidereal day. Moreover, a zodiac calendar is placed around the rim of the dial together with a month indication to further depict the position of the constellations at any given time of the year, with a perpetual calendar regulating the timing system.

The technical nature of the dial is heightened by subtle aesthetic touches.
The dark blue aventurine sky disc illuminated with diamond stars is surrounded by two crescents of baguette-cut sapphires in lighter shades of blue.
The blue becomes even lighter on the hand-guilloché lacquered disc bearing the indications of the month and zodiac signs.
The diamond hour-markers echo the stars, while the radiant bezel creates a splendidly luminous glow for this Grande Complication.

Master Grande Tradition Grande Complication by Jaeger-LeCoultre (Case Details)

Tourbillon & Silicon Escapement Parts
Contrary to the traditional construction based on both lower and upper bridges, a flying tourbillon is held only on the movement side and thus features a single cantilevered pivot.
The entire mechanism consists of 73 parts and measures 12.42 millimetres in diameter and 3.85 in height. Built of lightweight titanium, the carriage is reduced to its bare functional essence in order to provide an unobstructed view at the escapement system.
It is fitted on a lubricant-free ceramic ball bearing system. The 10-millimeter monometallic balance wheel with its regulation screws and its balance spring with Breguet overcoil has an inertia of 11.5 mg cm2 and beats at a high 4 Hz frequency.

The silicon parts of the escapement, such as the lever with its integrated pallets and the escape wheel, are thus clearly visible.
This escape wheel is a completely new design in order to meet the most recent demands in terms of lightness and easy handling. The lever with integrated pallets has a straight shape ensuring better aerodynamics. Using silicon parts, which require no lubricants, not only improves the long-term precision of the watch, but also reduces the inertia of the components by about a third in comparison to the classically used steel.
These improvements result in a 15 percent increase in the global efficiency of the escapement.

Movement
Manually-wound Jaeger-LeCoultre Calibre 945, launched in 2010, embodies the union between traditional watchmaking and contemporary technology with peerless elegance and refinement: all components are adorned with sunburst, circular-grained or snailed motifs, or feature a satin-brushed finish to accentuate the classical appearance of the construction.

The steel parts are polished and bevelled, the adjustment screws are blued and the screws for the settings are rhodium-plated.
Nonetheless, when viewing the dial side of the watch, the eye is drawn to another spectacular characteristic: the flying tourbillon is equipped with a high-tech escapement featuring the dark shimmer of silicon that creates a delightful contrast with the mirror polish of the grade 5 titanium tourbillon carriage.

This Grande Complication will premiere at Watches & Wonders in Hong Kong from September 30th to October 2nd, 2014.

Source: Jaeger-LeCoultre