The Patek Philippe Calibre 89, created in 1989 to celebrate 150 years of the company, is a simply extraordinary feat of engineering. It took nine years to create, of which the first five years were research.
Apparently an attempt to squeeze everything they know about watch-making into one piece, the Calibre 89 is a pocket watch, which is probably just as well, as at 1.1kg (nearly 3lbs) it could not sensibly be worn on a wrist.
See here for an amazing video showing how Patek Philippe make their watches.
The watch makes use of 33 complications and 24 hands to tell you almost everything you could need to know.
Naturally it gives you the exact time: everything from the year down through the month and day (including leap year indicator) to a split-second hand. It also tells you the hour in another time zone, and a great deal about the celestial bodies.
To be specific: it tells you when the sun rises and sets, and the phases of the moon, along with a star chart and sidereal (star rise and set) time. The watch also has a chronograph function, power reserve, chime and even a thermometer.
This masterpiece requires 1728 parts to do this. Patek Philippe only made four: three in different kinds of gold and one in platinum.
The yellow gold version returns to the auction hall in Geneva on November 15 - the last lot of Antiquorum's 35th anniversary auction on November 14-15.
It represents the chance of a lifetime for a collector.
Picture credit: http://marina.fortunecity.com/westindia/59/ppc89.htm