Patek Philippe is a renowned Swiss luxury watch brand known for their highly complex and intricate timepieces. The Sky-Moon
Tourbillon is the brand’s second most complicated watch, with a total of 12 complications. This watch was first released in 2001 and has recently been updated with a new version, the ref. 6002R-001, which replaces the previous model, the 6002G-010.
The Sky-Moon Tourbillon is a truly impressive watch, with a range of technical features that make it stand out from the rest. On the front of the watch, there is a perpetual calendar display that shows the day, date, and retrograde month, as well as mean civil time and a moon phase display. This watch also includes a feature that indicates the current position in the leap year cycle.
In addition to these features, the Sky-Moon Tourbillon also includes a minute repeater, which is a complicated function that chimes the time in increments of minutes. This feature is activated through a slide on the side of the case, a traditional method of activating the minute repeater function.
The back of the Sky-Moon Tourbillon is just as impressive as the front, with a display of astronomical complications. This includes a depiction of the night sky as seen from the Northern Hemisphere, with the portion of the sky visible above the horizon displayed within an oval and the points of the compass also shown for orientation. The orbit and phase of the Moon are also displayed on the back of the watch. The hands on the back of the watch show sidereal time, or “star time,” which is based on the amount of time it takes for a specific star to return to the same point in the sky. Sidereal time is slightly shorter than a solar day, by about four minutes. 
One of the unique features of the Sky-Moon Tourbillon is that it displays the time in both mean civil time and sidereal time. Mean civil time is the time in use at all locations in a given time zone and is based on the average length of a day, which is defined as the amount of time it takes for the Sun to return to a given point in the sky. The length of a true solar day can vary from the time shown on a clock by up to 15 minutes, known as the Equation of Time. Sidereal time, on the other hand, is not commonly used in everyday life and is of more interest to astronomers, as it is based on the movement of the stars rather than the Sun.
The Sky-Moon Tourbillon is a luxurious and highly technical watch that offers a range of complications for the wearer to explore. The new version of the 
watch, the ref. 6002R-001, is made of rose gold and features intricate engraving and enameling techniques such as champlevé and cloisonné. The previous version of the watch was made of white gold.
In conclusion, the Sky-Moon Tourbillon is a highly complex and impressive watch from Patek Philippe that offers a range of technical features, including a perpetual calendar, a moon phase display, and a minute repeater. It also displays the time in both mean civil time and sidereal time and includes a depiction of the night sky on the back of the watch. The new version of the watch, the ref. 6002R-001, is made of rose gold and features intricate engraving and enameling techniques. It is a luxurious and highly technical timepiece that is sure to impress any watch enthusiast.
