With the GMT, Robert Greubel and Stephen Forsey have focused their attention on displaying both a second time zone and universal world time as intuitively as possible. The second time zone is a highly practical complication and is greatly valued by connoisseurs, globetrotting businessmen, frequent leisure travellers and those with family and friends around the world.
The GMT offers an original method of visualising world time by means of a rotating three-dimensional globe in conjunction with a second time zone indication. A 25° inclined Tourbillon 24 Secondes escapement regulates the timing of the movement.
The globe simultaneously permits the visualisation of the time as well as the position of day and night across different continents via the 24-hour ring around the equator and the caseband window, which symbolises the position of the sun on the earth.
Offering a three-dimensional temporal representation, the rotating globe offers at a glance a highly original view of time all over the world and a new way of perceiving different time zones.
The terrestrial globe makes one complete rotation every 24 hours anticlockwise – the Earth’s natural rotational direction viewed from North pole – and the position of the continents can be easily cross-referenced with the time on the equatorial chapter ring, which is marked with the 24 time zones and day/night indication.
The night-time hemisphere – 18:00 to 6:00 – is indicated by a blackened half of the ring around the globe, while the daytime hemisphere – 6:00 to 18:00 – is indicated by a whitened portion. The latter is superbly enhanced by a lateral window cleverly integrated into the caseband that lets in light to symbolise daytime.
A worldtime disc bears the names of 24 cities, each representing one of the different global time zones with summer time indicated for those cities where it is applicable.
The beautifully crafted sapphire crystal disc is connected to the globe and by aligning the relevant city with the correct local hour on the outer chapter ring, the globe will indicate the correct worldtime.
The GMT features a 25° inclined Tourbillon 24 Secondes cage, one of Greubel Forsey’s major patented inventions.
The single inclined tourbillon cage undergoes rapidly changing positions with a high angular velocity, thus minimising the effects of gravity on the regulating organ and maximising timekeeping accuracy.
The 25° inclined Tourbillon 24 Secondes cage has been chosen for its chronometric virtues, reliability and compact size, which allows space for the other complications.