Designed and manufactured by Andreas Strehler in his workshop in Sirnach, the Lune perpétuelle has a perpetual display of the phase of the moon. 

With only four components, Andreas Stehler achieves almost eternity. Only almost, because the Lune perpétuelle's phase of the moon mechanism does require occasional adjustment. To be quite precise, it requires an adjustment by one day every 14'189.5383 years. 

The Sauterelle à Lune perpétuelle by Andreas Strehler is the most precise phase of the moon ever built. And by some margin. Approximately 11'000 to 14'000 years.

In daily life, this means: Had a mammoth-hunter at the end of the last ice age set the phase of the moon of his Lune perpétuelle and had he worn it through the ages, it would soon be time to make the first adjustment of the phase of the moon. And yet, Andreas Strehler – being the perfectionist he is – did not allow the press team to use the term "absolute precision" for the Lune Perpetuelle.  And this, although the renowned specialist for astronomical gears and professor for mathematics and astronomy, Robert Baggenstos has verified this precision.

Technically, the Lune perpétuelle is based on the Sauterelle, presented at last year. Like the Sauterelle, also the Lune perpétuelle features Andreas Strehler's unique Remontoir d'égalité, delivering a constant supply of energy to the escapement.

According to Andreas Strehler's concept of options, the client can also order the phase of the moon function based on the Cocon. This option will also be available for future models. 

The Lune Perpetuelle is another example of Andreas Strehlers ingenious designs. Or in the words of the Jury of the Prix Gaïa: "His minimalistic movements conceived like true living organisms."

Implemented using only four components, Andreas Strehler's phase of the moon mechanism achieves its precision partly because it is continuously moving, driven by the gear train. Conventional phase of the moon mechanisms are only moved forward once a day. 

Further, Andreas Strehler's clever combination of inner and outer toothing as well as the use of prime numbers for the number of teeth makes it possible to mechanically achieve complex fractions with an integral number of teeth. This leads to the high precision of the phase of the moon mechanism.

In the development of this mechanism of the Lune perpétuelle, Andreas Strehler followed his father's dictum: "It is always worth to invest in good tools if it helps to do a job better" and wrote a computer code which helped to find the ideal number of teeth for the cogwheels.