Watches that provide all sorts of attractive extra-features (complications) without employing any electricity or chips have always been pretty popular, especially with the people with enough money to actually afford them. And that's exactly the case with the Sky Chart Grand Complication, a timepiece which might target especially those very rich people in love with astronomy.

Pretty much as in the case of many other grand complication watches, the Sky Chart Grand Complication is built around a very complex internal mechanism, in this case the Caliber 240 LU CL, a self-winding movement coveted for the elegance of its layout and its extremely compact design.

The movement's 22K. gold mini-rotor, situated in an off-center position, has a large mass despite its unusually small diameter, as the inlaid design of the rotor made it possible to reduce the height of the movement to 2.53 millimeters. The mechanism features no less than 45 jewels, uses a Gyromax balance wheel and generates up to 21600 vibrations per hour. Additionally, the device offers a pretty impressive power reserve, of around 48 hours.

As mentioned earlier, the functions provided by the Sky Chart Grand Complication are quite spectacular. Thus, the device displays the night sky of the northern hemisphere, which rotates counterclockwise on its dial, showing the angular progression of the stars relative to the meridian passage of Sirius. At the same time, the display shows the meridian passage and phases of the moon. Two hands from the center show the hours and minutes of mean solar time on a dial with Roman numerals.

The case is manufactured from yellow gold with a sapphire crystal face and measures around 43.10 mm in diameter. Furthermore, the device is water resistant down to 30 meters, while the size of the case and buckle match the overall design of the watch (20 x 18 mm).

The Sky Chart Grand Complication from Patek Philippe has a very high price, namely around 200,000 US dollars, which means that the number of customers who actually own such a device is (and will be) pretty limited.