Monochrome Watches
An online magazine dedicated to fine watches

The New Ochs und Junior Ochs Line Moon Phase Selene in 39mm & 42mm

O&J's astronomical time machine returns on special Ochs-blue and two sizes.

| By Robin Nooy | 3 min read |

Known for its ingenious simplistic approach to watchmaking, the Swiss brand of Ochs und Junior does things a bit differently. Not bragging about how many parts they stuffed in a watch, but rather how few they put in. Take for instance this Ochs und Junior Ochs Line Moon Phase, or Selene, as the company also calls it. Designed by Ludwig Oechslin, this adds only 5 functional components on top of the base movement to precisely indicate the phases of the moon. It’s really clever stuff! New to this lunar collection is a non-customisable variant in a 39mm or 42mm titanium case.

The case is machined out of grade 5 titanium and comes with visible machining and milling traces, a deliberate design choice by Ochs und Junior. The two-part construction is water-tight to 100m, due to its screw-down crown. The 39mm or 42mm wide case is a very reasonable 11mm in height only. Thanks to the short lugs, and partially tucking in the strap end underneath the bezel, it will wear smaller than its dimensions suggest. The sapphire crystal on top finishes it all off.

Ad – Scroll to continue with article

The dial is finished in a matte navy blue shade called Ochs Blue. The hour indices and hour and minute hands are rhodium-plated, providing a nice contrast to the rich hue of the dial. The central second’s hand is also finished in Ochs Blue. The dial, a functional component of the module as seen below, has cutouts for the date and moon phase indications. The silver disc at noon represents the sun, with the central axis for the hands representing Earth. New moon is indicated when the moon is hidden between the Earth and the sun, and the dark disc sits at 6′. A full moon is when the brighter disc sits at the bottom of its trajectory.

Just 5 components are needed to indicate the phases of the moon.

The base movement used for the Selene is the tried-and-tested ETA 2824-2, running at a rate of 28,800vph and providing 38 hours of power reserve. This is fitted with a moonphase module using only 5 additional parts, one of which is the dial itself. This module is calculated to a lunar cycle of 29.5306122449 days, which is very close to the real-time average lunar cycle of 29.530589 days, and certainly far more accurate than the 29.5-day average most watches rely on. This means the Selene’s moonphase is accurate for 3,478.27 years before it’s off by just 1 day instead of once every 2 years. That shows you just how ingenious this system is!

The new Ochs und Junior Ochs Line Moon Phase or Selene is worn on a handmade Ecopell Enzian leather strap, fitted with the signature O&J buckle in titanium. This buckles tucks in the short end underneath the long end, eliminating the need for keepers. It’s not limited, nor is it customizable and it can be pre-order directly through the brand’s website for a price of CHF 5,500 incl. VAT.

For more information, please visit

1 response

Leave a Reply