Patek Philippe celebrated their 175th anniversary in 2014, and to commemorate this remarkable milestone, released a series of impressive references, all limited editions, epitomizing the horological mastery that has led to the enduring success of this esteemed manufacture. The reference 5575 is no exception, being the first timepiece in which Patek Philippe combined a world time complication with a moon phase following the lunar cycle. Patek Philippe engineered an entirely new caliber for this timepiece (and the corresponding ladies' version, the reference 7175 in rose gold), the caliber 240 HU LU ("heures universelle lune"), an ultra-thin automatic movement with a 22 karat gold microrotor.

The moon itself is highly realistic, yet no less elegant, and is stunning against a nocturnal starry sky, the whole skyscape made possible by a complex and intricate metallization of the two moonphase discs. Instead of Paris, Geneva represents Central European Time on the external rotating disc, a nod to Patek Philippe's Swiss heritage. The hour hand is in the form of the Southern Cross, a constellation often used for navigation, particularly in the Southern Hemisphere where it is visible for the entire year. Cased in elegant white gold, this example is presented in like new condition, complete with all of its original accoutrements.