automatic movement with date window from Nomos. It was introduced in 2006 and remains in production as of 2019.
The 2005 introduction of the Alpha movement family was an important turning point for Nomos. Although based on the preceding Nomos 1 TSP, it was largely constructed in-house rather than being a refinished ebauche. This was followed in 2006 by the Nomos Epsilon, the first Nomos movement with automatic winding. Both movements feature a gear train similar to the classic Peseux 7001, but placed in a new enclosure based on the classic Glashütte three-quarter plate design. Nomos updated many of the components, adding hacking seconds, and completely reworked the finishing with rhodium-plated surfaces, blued screws, Glashütte Stripes, and Glashütte solar grinding or Langeleist-Perlage.
The automatic movements consist of Epsilon, Zeta (with date), and Xi (with GMT or world time disc). All three movements measure 13¾ ligne (31 mm) in diameter, but Epsilon is thinnest at 4.3 mm. Like the Nomos Beta and Delta, the Zeta uses a date wheel mounted outside the movement rather than stacked between the bottom plate and the dial. This allows the movement to be just as thin as the non-date Epsilon version.
This movement is officially named using the Greek letter “ζ”, but Nomos often writes it as “Zeta”.
The first version of the Epsilon movement had 24 jewels. In May 2007, Nomos switched to a new version with 26 jewels. One wheel in the automatic winding system was set in two extra jewels, allowing better winding efficiency and durability thanks to reduced friction.
This movement is part of a family of Nomos movements produced since 2005. The movement is partially made in-house, though the assortment is supplied by a third-party. It was supplanted by the in-house Nomos Swing System family starting in 2014.