The Celestial series within Patek Philippe's collection has, since 2002, presented the night sky as it appears from Geneva using a system of superposed rotating disks. Reference 6105G-001 extends this tradition by adding a complication that has previously appeared in Patek Philippe pocket watches and supercomplication pieces but never in a wristwatch in the regular collection: the display of the times of sunrise and sunset for Geneva, updated continuously across the year according to the annual cycle of the Earth's axial inclination. The development required more than five years and resulted in six patent applications.
The sunrise and sunset mechanism uses a pair of ovoid cams, one for each indication, whose contours reflect the geometric change in the Earth's double-feeler spindle axial tilt across the year. A double feeler-spindle, 0.48 mm in thickness, reads the position of each cam continuously via two flexible arms, transmitting the result through a rack system to the hands at the periphery of the dial. These two hands indicate sunrise on the right-hand scale and sunset on the left, both using the same numbered date disk to display their values. A patented corrector system at nine and 10 o'clock allows civil time and the sunrise/sunset indications to be adjusted simultaneously during the transition between Summer Time and Winter Time, requiring only a single press at each position.
The 47 mm white gold case carries an X-shaped motif worked in relief on the caseband, extending to the solid gold case back, where it frames an engraved Calatrava Cross. Two crowns manage separate functions: one at four o'clock for time-setting, one at two o'clock for the astronomical displays, the latter using a patented bayonet disconnecting system that requires pressing and turning to engage, preventing accidental adjustment. The black composite strap features a pierced X-shaped motif that matches the caseband, secured by an invisible system that eliminates traditional lugs. Calibre 240 C LU CL LCSO comprises 426 parts, 121 more than the base Celestial calibre, in a height of 7.93 mm, an increase of only 1.12 mm despite the addition of the entire sunrise/sunset mechanism and its corrector system. A 22K gold off-centre mini-rotor delivers a power reserve of between 38 and 48 hours.