Baselworld 2010: Patek Philippe Ref. 5140 in rose gold and platinum

Baselworld 2010. Another watch that Patek Philippe made available with more choices as to the precious metal the case is built in is the Ref. 5140. The Ref. 5140 is a perpetual calendar watch, like the Ref. 5159R also released in 2010.

The Patek Philippe 5140R, in rose gold with a brown dial

Most watches with a date and month display has the date wheel or pointed set to move one day every 24 hours, and the month wheel or pointer set to move at the 31st of each month. Since not every month has 31 days, five time a year, you will have to correct the date.

The Patek Philippe 5140P, in platinum with a blue dial

With perpetual calendars like the Ref. 5140, when you set the watch, you set the date, month and year. The year is set in the sub-dial at the 3 o'clock position with the numbers 1, 2, 3 and 4. Four representing the leap year. The month is also set in the same sub-dial. The date is displayed via a pointer in the sub-dial at the 6 o'clock with works in conjunction with the hands on the sub-dial at 3 o'clock so that in months with only 30 days, the month changes on the 30th and not the 31st, and the day hand will skip the 31st and go straight to the 1st. In February, the month changes to March on the 28th and not the 31st, and the day hand will skip the 29th, 30th and 31st and go straight to the 1st, except of a leap year. On a leap year (i.e. the 4th year), the month changes to March on the 29th and not the 28th.

While not the most complicated of "complications", the perpetual calendar is our favorite.

Calatrava. The Ref. 5140 displays the month, day and date are all displayed via sub-dials rather than in windows of apertures which would display the month by an the words "APR" or "MAY" and the day with a "MON" or "TUE" display. We find this format to be more elegant.

For comparison in the 5159 displays the year, month and day in windows

However, there is an advantage to using sub-dials, it allows for a slimmers case.

Profile view of the Ref. 5140 above, and the 5159 below.
Not using displays in apertures or windows means not having
to use month and day wheels, which allows for a slimmer profile.

By using sub-dials rather than windows or apertures, the watch can be kept slimmer. Another Patek Philippe innovation which allows the watch to be kept very slim is the mini-rotor.

Ref. 5140 on the left. Ref. 5159 on the right.

The mini-rotor is placed in an off center position. The smaller size of the rotor allows it to be placed beside the movement rather than behind it and makes it possible to build ultra thin self winding watches. Patek Philippe rotors are crafted from 21K or 22K gold because the high specific gravity of the precious metal optimizes the kinetic energy yield.

The Ref. 5140 movement, the 240 Q is all of 3.88 mm thick. Very impressive for a perpetual calender watch with a moon phase display to boot.

About Patek Philippe. Patek Philippe and Co. was founded in Switzerland in 1851. The companies emblem, the Calatrava Cross, was adopted by it at the end of the 19th Century. It is acknowledged as one of the finest, if not the finest, watchmaker in the world.