Another Tonda 1950 in steel, this time with moon phase. This is the Parmigiani Fleurier Tonda 1950 Lune
The moon phase or lunar phase is the shape of the sunlit portion of the Moon when you look at it from Earth. These phases change cyclically as the Moon orbits the Earth, according to the changing positions of the Moon and Sun relative to the Earth.
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The Moon’s rotation is tidally locked by the Earth’s gravity, therefore the same lunar surface always faces Earth. This face is variously sunlit depending on the position of the Moon in its orbit. There are four principal lunar phases: new moon (0% sunlit), first quarter, full moon (100% sunlit), and third quarter (also known as last quarter).
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Timing of the Moon’s phases shifts
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The average calendar month, which is 1⁄12 of a tropical year, is about 30.44 days, while the Moon’s phase (synodic) cycle repeats on average every 29.53 days. Therefore, the timing of the Moon’s phases shifts by an average of almost one day for each successive month. (Lunar year=354 days.)
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The approximate moon phase can be calculated for any date by calculating the number of days since a known new moon (such as January 1, 1900 or August 11, 1999) and reducing this modulo 29.530588853 (the length of a synodic month). Can you imagine how watch makers manage to create a complication like this?
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Watches with a moon phase
The Breguet Classique Phase de Lune 7787 isn’t new but the line is extended with new models, available in pink or white gold
Completely new, with an updates movement: this is the Glashütte Original Senator Excellence Perpetual Calendar
The A. Lange & Söhne 1815 Annual Calendar is the ‘entry-level’ Lange model with full calendar, available in pink or white gold
The Chopard L.U.C Perpetual Chrono Platinum is new as it features a platinum case with blue dial. And limited, just like the 2016 gold model
The A. Lange & Söhne 1815 Tourbograph Perpetual Pour le Mérite is a showcase of high-end watchmaking with some great complications
This Rolex Cellini Moonphase Everose (reference 50535) is the first Rolex with moon phase in almost seventy years
This Chopard L.U.C Lunar One Platinum is the latest perpetual calendar with moon phase from Chopard’s L.U.C collection
The Christiaan van der Klaauw Real Moon Stella Nebula has a dial from ammolite, a gemstone formed from 71 million years old shells
The moon phase complication of this Christiaan van der Klaauw Real Moon Joure Horizon is so accurate it deviates one day in 11,000 years