In 1721, astronomer royal Edmond Halley made the first of many meridian measurements at the Royal Observatory in Greenwich, London, that helped to establish the concept of a zero-point from which the entire world could measure its time.
Initially, British seafarers benefited from Greenwich Mean Time (the “mean” refers to the average deviation throughout the year between the real and theoretical positions of the Sun) as British clock-makers in the UK were among the first to use marine chronometers.
Today, we still use GMT as shorthand for a universal reference point, and during the 1950s it was with reference to Greenwich that Rolex created the GMT-Master for Pan-Am pilots eager to keep one eye on time at home, even as the standard was being usurped by the infinitely more drab Co-ordinated Universal Time (UTC). Of course, there are Swiss watchmakers who market their models as UTC instead – and a great many more diplomatically opt for “dual time” or similar.
Engineering a GMT-equipped watch is not the hardest thing to do; halving the normal gearing for the hour hand gives you your 24-hour reference. But there are two ways to implement the complication, and one has an edge. If you link the GMT hand not to the hour hand as one might expect, but to the minute hand, it allows for the setting of “home”, or GMT, time and subsequently the easy, isolated, adjustment of the hour hand without troubling the minute or date.
This is the method adopted by Rolex’s GMT-Master II, newly released this year with an updated movement (and a 70-hour power reserve), and its sibling watch from Tudor, the handsome Black Bay GMT. Tudor’s GMT is a throwback in other ways, too, favouring aluminium bezel inserts over ceramic, and a sleeker, more vintage-inspired case shape. It’s also arguably the more versatile of the two watches, with a choice of brown leather strap, woven fabric or a sturdy stainless steel bracelet.
If you want dual-timezone functionality without the old-school looks, Hermès has a typically fresh, whimsical approach. The palladium-cased Slim d’Hermès GMT – recognisable for its svelte lines and custom-designed Philippe Apeloig typeface – adds a second timezone dial like no other, with a jumble of numbers at 10 o’clock. It’s easier to read than it looks, we promise. You also get day/night indicators for both your local and home timezones, and underneath, it’s powered by a high-grade micro-rotor movement from Hermès’s in-house watch manufacture.
This article was originally published by WIRED UK
