With the Seamaster Aqua Terra GMT, Swiss watch brand OMEGA introduces a new member of its exclusive Co-Axial family of movements. The Co-Axial calibre 8605/8615 is the first of OMEGA’s proprietary movements to be equipped with a GMT complication, meaning that along with the central hour, minute and seconds hands, there is a GMT hand which completes one rotation every 24 hours, making it possible to keep track of the time in two time zones.
The 43 mm case is available in a choice of metals: 18 Ct red gold or stainless steel or, in a bicolor version in 18 Ct red gold and stainless steel. The sapphire crystal on the screw-in caseback allows a clear view of the extraordinary Co-Axial movement inside. The watch is available with either a bracelet in the same metal as the watch case or with a black, brown or blue leather strap.
The dial is distinguished by the teak pattern associated with the Aqua Terra collection. The vertical lines are reminiscent of the wooden decks on luxury boats. The applied 18 Ct gold brushed and polished indexes are coated with white Super-LumiNova and the facetted hands are crafted from 18 Ct white or red gold. Like the indexes, they are coated with white Super-LumiNova which allows ease of reading in all light conditions. The GMT hand’s red arrow makes it easy to distinguish the two time zones.
At the heart of the Seamaster Aqua Terra GMT is the Co-Axial calibre 8605/8615. It is part of the family of movements OMEGA introduced in 2007 built around the first practical new watch escapement to be developed in some 250 years. The Co-Axial escapement in the OMEGA calibres is used in conjunction with a free sprung-balance and its function differs considerably from that of a conventional lever escapement with index. The watch’s rate can be adjusted by modifying the moment of inertia of the balance by means of two gold regulating micro screws embedded in the circular balance.
This design avoids the disturbing effects of contact between the balance-spring and the index pins and therefore ensures that the stability of rate offered by the Co-Axial escapement is maintained over long periods of use. The result is reduced friction which means that there is almost no need for lubrication; the Co-Axial calibres have long service intervals and the Seamaster Aqua Terra GMT, which is also equipped with a silicon balance spring, is delivered with a four-year warranty.
The Co-Axial calibre 8605/8615 is the first in the family to be equipped with a GMT complication. Its GMT hand has a diamond-polished red arrow, making it easy to track time in a second time zone or GMT display. Intriguingly, the GMT hand can also be used for compass orientation: when the watch is held parallel to the ground with its hour hand pointed in the direction of the sun, the GMT hand, when it is adjusted to the same time on the 24-hour GMT display, will indicate north in the northern hemisphere.