The Seamaster Aqua Terra > 15,000 gauss was the first watch to feature OMEGA’s revolutionary Co-Axial calibre 8508, which is resistant to magnetic fields greater than 15,000 gauss. This far exceeds the levels of magnetic resistance achieved by any previous watch movement and solves a problem that has always challenged watchmakers. The 41.50 mm stainless steel Co-Axial chronometer presented on either a matching bracelet or a brown leather strap.
The technology developed by a team of ETA, Asulab, Nivarox FAR and OMEGA engineers led to the first prototype of the movement. Unlike other efforts to combat the effects of magnetism, the OMEGA movement does not rely on a protective container inside the watchcase but on the use of selected non-ferrous materials in the movement itself. Several patents are pending for the new movement which, even after exposure to a magnetic field greater than 15,000 gauss, still performs at a chronometric level as defined by COSC.
With magnetic shield casing (0-1000 gauss).
With non magnetic movement resisting > 15,000 Gauss.
With magnetic shield casing (stops working over 1000 gauss).
"…Magnetism has always been an issue for watchmakers."
Previous attempts to resist magnetism relied on protective inner cases but these watches were not equal to the challenge of the increased strength of permanent magnets. The inner cases also blocked the view of the movement, thus limiting the possibilities of a date window display. The Seamaster Aqua Terra > 15,000 gauss doesn’t need to be protected by an inner case so its Co-Axial calibre 8508 is visible through asapphire crystal in its caseback. There is also a date window at 3 o’clock.