Calibre 410 was developed in 1969 as a variation on the much loved and admired El Primero, It has the accuracy of the El Primero chronograph combined with a triple calendar and moonphase indications.
Zenith’s El Primero had an exceptional speed of 36,000 vibrations an hour, corresponding to 1/10th of a second precision. That same year, Manufacture Zenith equipped the calibre with the two additional complications of the triple calendar and moonphase indications. In 1969 the name of the movement was the El Primero 3019 PHF, it later became referenced as the 410. The movement is built around a column wheel and endowed with a 50-hour power reserve. Calibre 410 was phased out 2000, but now Zenith is reviving it as a a 500-piece limited edition series featuring a slate grey dial.
Almost half a century after its creation, El Primero Calibre 410 reproduces the original function layout in a distinctively 1970s spirit. The days and months are counted off at 10 and 2 o’clock respectively, while the date is still located between 4 and 5 o’clock. Merging into the hour subdial at 6 o’clock, the moonphase depicts the revolutions of the night star through a special-shaped aperture with two rounded cut-outs reproducing the dark part of the moon. The successive phases (waxing moon, full moon, waning moon, new moon) are displayed. The disc bearing two moons is driven by a 59-toothed wheel corresponding to two lunar cycles (2 x 29.5 days).
The 42mm watch steel cased watch displays on-trend curves with alternating polished and brushed finishes. The watch also features rounded chronograph pushpieces and snailed counters which contrast with the sunray dial motif. Rimmed by the tachometric scale on the opaline inner bezel ring, the rhodium hour-markers ensure perfect readability. As an extra touch of branding, the Zenith star on the tip of the blue central chronograph seconds hand sweeps over the dial, and on the caseback, the El Primero Calibre 410’s 390-part mechanism is clearly visible through the sapphire crystal case-back.
