The WANDA – the simple bestseller of the Aarberg watch manufacturer RB Baumgartner AG Swiss Watchmaking is now equipped with a moon phase display and becomes the WANDA MOON.

Even before the advent of moon phase watches and how they work, the phases of the moon and the moon itself have preoccupied people. Not only because the earth’s satellite travels evenly around the earth in about 400,000 kilometres, but also for the prediction of high and low tide, the course of the moon had to be taken into account. For thousands of years, its regular rhythm has formed the basis for the division of our calendar into weeks and months, which is still valid today.

Photo reference: Nadja Frey and Karin Bill


Reto Baumgartner and his team are also fascinated by the earth’s satellite – so much so that they have added a moon phase display to the elegant, clear dial of the WANDA.

The WANDA collection is built on geometric and clear lines inspired by contemporary architecture. The bezel of the WANDA has been adapted for the new WANDA MOON to integrate the Sellita SW 280 movement. The diameter of 40mm remains unchanged.

The dial of the WANDA MOON is available in three trendy colours: opalin silver, sun blue and black lacquered. It features 12 rhodium-plated indexes, a date display at 3 o’clock and, as a new feature, the moon phase at 6 o’clock.

WANDA MOON in Opalin Silver


How a moon phase watch works

A moon phase simulates the movement of the moon towards the earth. In a semi-circular cut-out on the dial, the moon slowly advances on the slowly rotating moon disc of the movement.

Technically, there is a slight problem with this. Since a complete moon phase only lasts 29.5 days and is therefore technically difficult to realise, the moon phase is taken twice on one disc. This double moon is quite audacious from a lunar point of view, but it has the advantage that the representation of two moon phases with a rotation of 59 days and thus also 59 teeth of the gear wheel can also be technically implemented. This means that the speed of the gear can be adapted to the speed of the day. Another advantage of this double moon disc solution is that with moon phase clocks of this function, the moon disc can be coupled to the date mechanism. If the date moves forward, the moon phase also moves forward through a small intermediate wheel construction.

However, due to the calendar, there is a small disadvantage. Because the moon phase is exactly 29 ½ days and 44 minutes plus 3 seconds, the moon phase has to be adjusted by one day by hand every three years.

WANDA MOON in Sunblue


Range expansion with three beauties

In addition to the brilliant three new WANDA MOON models, celestial enthusiasts, hobby astrologers and friends of mechanical watches will find a beautiful, round assortment of different mechanical watches in Reto Baumgartner’s small Aarberg atelier – from fine ladies’ models framed with synthetic diamonds to pilot’s watches steeped in history to chronographs rich in complications – with or without moon phase display.


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