In 2002 Patek Philippe released the Celestial (Ref. 5102) which is considered one of the most significant and unusual horological complications ever developed. A remarkable rendition of the Northern Hemisphere's celestial chart is fitted dynamically upon the wrist for the first time. The celestial chart rotates counterclockwise, showing the angular progression of stars relative to the meridian passage of Sirius. At the same time, the meridian passage and phases of the moon can be seen. 25 trillion (25,000,000,000,000) ratio combinations were researched by Patek Philippe to determine an astonishing degree of accuracy for all the Ref. 5102's displays.