Down The road, Arnold’s chronometers would serve significant roles in legendary voyages, because the devices assisted navigators compute their longitude. Declaring the winner from the race to build the 1st computerized chronograph in 1969 is contentious business, so Zenith’s “El Primero” moniker is arguable. That’s the title in the movement https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/