For Patek Philippe's 175th anniversary in 2014, the firm has reinterpreted this legendary model, giving it a hauntingly poetic moon phase display. To help it venture into these new technical and aesthetic dimensions, the manufacture has developed a new version of ultra-thin self-winding movement: the caliber 240 HU LU. The engineers have dispensed with the usual aperture and its disk adorned with two moons; instead, a single, large, richly atmospheric moon turns clockwise, at the center of the dial, against a star-studded nocturnal sky. The effect is achieved with two very thin disks of mineral glass. The lower disk, depicting the moon, completes a rotation in a lunar month. The fixed upper disk is a heart-shaped mask; its outline reveals the changing visible portion of the moon night after night with astonishing accuracy. A complex new metallization technique has produced a moon whose face stands out against its starry background with almost photographic realism.

The present reference 5575 was made in a limited series of 1,300 pieces in white gold and is highly sought-after by collectors worldwide.