You don't have to be an astronaut to wear the Rolex GMT Master II watch, or a space engineer to figure out how to use it.

Long before this model gained popularity with astronauts - Jack Swigert wore it on the troubled Apollo XIII mission - it soared to fame with commercial pilots.

As a matter of fact, Rolex originally created the GMT Master in 1955 to allow Pan Am pilots on transatlantic flights to simultaneously monitor both GMT and local time.

Pan Am is no longer flying (much to my relief), but the GMT Master is still ticking along half a century later, with a redesigned look sporting a new winding crown, and a new security clasp with a rapid extension link on the Oyster bracelet. One of the models also has a two-colour dial to differentiate day from night.

Just set the 24-hour hand and the 12-hour hand to the same hour while in your local time zone, then re-adjust the hour hand and the date either ahead as you travel east, or back as you travel west. The movement in the GMT Master II is unique because it allows you to adjust the hour and the date backwards just as easily as forwards.

If you are a frequent traveler who whizzes in and out of different time zones, then you should not leave your home without this solid and elegant classic watch. If, on the other hand, you don't fly but like the aviation lore, you might prefer the understated elegance of another Rolex watch, the more moderately priced Air-King.

Of course, you don't have to be a pilot to be a high flyer with a GMT II watch around your wrist. Paul Newman, usually associated with another Rolex model, the Daytona, sports a GMT Master in "When Time Ran Out" (maybe he didn't pay attention to the adjustable time zone feature?) And Dustin Hoffman received the GMT II watch as a gift in the "Marathon Man."

So there you have it -- the aviation myth and Hollywood glamour all wrapped up in the GMT Master. Now, if it could only cure jet lag!