The Patek Philippe Celestial

If you want a watch that will not only tell you when it is, but where you are -- in terms of the cosmos -- the Patek Philippe Celestial is the stargazer of choice. The sublime Celestial wristwatch features an accurate moving display of the stars and the moon (even during daylight) from the perspective of the northern hemisphere. No telescope needed.

This is no simple miniaturized mural of the stars. The star chart delineates the nocturnal sky precisely from a photograph taken at the Geneva observatory. The ellipse etched within the outer sapphire crystal actually frames the angular part of the sky that can be seen from most points in the northern hemisphere sharing the same latitude (46 degrees, 20 minutes).

The Celestial features three layers of sapphire crystal discs, which create depth above the deep blue watch face. Each disc plays a role in the watch's astral timekeeping by acting as a gear that uses hundreds of tiny teeth surrounding the outer rim of the crystal.

The discs revolve ever so slowly, rotating the canopy of stars one revolution over a period of 23 hours, 56 minutes and several seconds; rotating the moon one revolution in 24 hours, 50 minutes and nearly 30 seconds; and creating the appropriate phases of the moon for a complete lunation (29 days and nearly 13 hours).

Each Celestial wristwatch is composed of 301 unique parts. And according to Patek Philippe, it has the one combination out of about 25 trillion available that most accurately tells time, rotates the star chart, and records the moon's orbit and lunation. Of course, a computer was used to crack the combination…no Geneva watchmaker is that good.

About 18 months are needed to create each watch; only 30 to 35 are built each year. The Celestial's body is 18K white gold, with two knobs at the edge of the case: one winds the watch and adjusts the time; the other adjusts the astronomical indications. A user-friendly CD-ROM is included for adjustment instruction.

Available at select jewelers worldwide, the Patek Philippe Celestial retails for $137,500, which may seem a bargain next to its "big brother," the watchmaker's double-faced $620,000 Sky Moon Tourbillon. This wristwatch tells standard time on the front and has a celestial calendar on the back. However, as only two or three Sky Moon Tourbillon watches are manufactured each year, might we suggest the Celestial?