Vintage Patek references up until the 3970/3940 boasted a very rich enamel moonphase with handcrafted accompanying gold stars and moon disc. For reference, slide 2 of this post shows a 2499 moonphase and slide 1 is of a 3970 moonphase. The enamel moonphase of the 2499 is a very rich navy blue that has a wonderful and radiating texture. The blue is engraved and filled with the gold stars and moons so they don’t sit on top of the disc. It’s one of the best moonphase discs I have ever seen in my life.

The 3970 standardises the moonphase creation process. No longer was the disc engraved or the stars shaped in by hand. This is evident in the giant leap in tolerances of star shapes and lines. It has become significantly more uniform from the 3970 onwards. Enamel is no longer used and the blue shade for the background is very dark compared to the rich tones of the enamelled predecessors. The moon and stars of both the 3970 and the 2499 are mirror polished, which indeed was the case for all Patek references with moonphase pre 5970.

The stars on the 3970 differ dramatically from the 2499 with very poignant thick black borders sitting on top of the moonphase disc. The borders hold the mirror polished gold stars within a recessed area just below it. This became the leading style for the stars until the later production stages of the 5970. This means icons such as the 5004, 5020 and the likes all followed the 3970 configuration. The 5970 served as a transitional reference for moonphase production. Earlier models had the same configuration as the 3970. Later on the stars lost their strong prominent border and were finished, along with the moon, in a frosted fashion, adding an exciting layer of depth. I’m inclined to say the transition happened with the introduction of the 5970j though I am not yet prepared to write off the existence of a 5970r with the frosted configuration. For modern/post vintage moonphase discs, it is cut from a wafer of corundum crystal. Gold is condensed onto the moonphase disc via a vacuum process through a photographic mask to deliver their shapes.

Every Patek wristwatch with moonphase pre 2499 had a similar enamelled moon disc to the 2499. This includes 97975, 96, 130 (not a typo), 1526, 1518, 1527, 1591, 2438 and 2497. Post 2499 introduction had a handful of references follow suit such as the 3449, 3448 and 3450. The style of the moon disc from the 3970/3940 followed every reference until the later stages of the 5970 for perpetual chronos. It is worth noting that most white metal calendars pre early 2000s like the 2499, 3448, 3940, 3970, 3974, 5004, and 5020 had a yellow gold moonphase for a white metal cases. This changed around the late 90s/early 00s. Following the 5970 every reference followed suit of the new frosted moonphase style with small exceptions.

Annual calendars went through a transitional period with the 5146. Early models featured the black border for the stars as seen in the 3970. Later in the 5146’s production it changed to the frosted configuration. This change was cemented with the arrival of the 5205 in 2010 which all came with the frosted moonphase interpretation. With perpetual only wristwatches, we also see a transitional phase from 3970 style to late 5970 style moon phases with the 5140 introduced in 2006. Just as with the 5146, earlier variants carried on the 3970/3940 tradition most noticeable in the strong black borders of the stars. Later down the line the moonphase configuration was switched to that of the borderless star frosted style.

In Patek’s current catalogue every wristwatch with moonphase follows the frosted configuration with the exception for the 6002. The 6002 marks the first return of enamel to a Patek moonphase in almost 30 years. “The circumference of the moon is elaborated in relief and enclosed with enamel”. But where things get cool, and I mean really cool, is the moon. To artistically depict the moon’s cratered surface, white, grey and black enamel are used in graduations. It is the best moon I have ever seen and one that is the product of painstakingly patient craftsmanship.

The 5575 and 5102/6102 also represent an interesting evolution of the PP moonphase. However, as they are isolated to very few references, I thought it would be better to focus on them individually at a later date. 

All pictures and watches are mine bar the 6002g.