A Custom Made Creation
Reference 57260, bearing the Hallmark of Geneva, is a double-dial horological masterwork of hitherto unimaginable complication and technical innovation, bearing the Hallmark of Geneva. It has been conceived over a period of eight years by a team of three of the company's master watchmakers.
Made using the classic principles of watchmaking, along with resolutely 21st-century thinking, this watch is an entirely original creation exhibiting a total of 57 complications, several of which are entirely new and unique. The new complications that were required to be incorporated including, among others the multiple calendars and double retrograde rattrapante chronograph, had never previously existed and therefore had to be calculated, designed, and developed from scratch, thus a completely new calibre of movement. Furthermore, the mechanisms of the more familiar complications have been modified, reinterpreted, and redesigned.
The conception and realization of the Reference 57260 watch has required not only a huge leap of imagination, but also an exceptional level of mathematical understanding and craftsmanship. The successful completion of this watch in the 260th anniversary year sets a new benchmark in horology. In addition, the legacy of research and skills developed during its construction is the greatest contribution to the advancement of mechanical watchmaking since the 1920s, indeed in the history of measuring time.
The Reference 57260 watch takes its place in a proud lineage of exceptional creations that punctuate history, in particular the history of art, which often stem from the encounter between a major collector who commissions them and the expertise of an artist or a great Maison.
COMPLICATIONS LIST
Time Functions
1. Regulator-type hours, minutes and seconds for solar meantime
2. Visible spherical armillary tourbillon regulator with spherical balance spring
3. Armillary sphere tourbillon
4. 12-hour second time zone hours and minutes
5. Indication for 24 world cities for world-time
6. Day and night indication for the 12-hour world-time
Perpetual Calendar Functions
7. Gregorian perpetual calendar
8. Gregorian days of the week
9. Gregorian months
10. Gregorian retrograde date
11. Leap-year indication and four year cycle
12. Number of the day of the week (ISO 8601 calendar)
13. Indication for the number of the week within the year (ISO 8601
calendar)
Hebraic Perpetual Calendar Functions
14. Hebraic perpetual calendar with 19-year cycle
15. Hebrew name of the day
16. Hebrew name of the month
17. Hebrew date indication
18. Hebrew secular calendar
19. Hebrew century, decade and year
20. Indication for the number of months in the Hebraic calendar year
(12 or 13 months)
21. Indication for the Golden Number with 19-year cycle
Functions of the Astronomic Calendar
22. Indications for the seasons, equinoxes, solstices and signs of the
zodiac with "sun" hand
23. The sky chart (calibrated for the city of the owner)
24. Sidereal time hours
25. Sidereal time minutes
26. Hours of sunrise (calibrated for the city of the owner)
27. Hours of sunset (calibrated for the city of the owner)
28. Equation of time
29. Length of the day (calibrated for the city of the owner)
30. Length of the night (calibrated for the city of the owner)
Lunar Calendar Function
31. Phases and age of the moon, one correction every 1027 years
Religious Calendar Function
32. Indication for the date of Yom Kippur
Functions of the 3 Column-wheel Chronograph
33. Retrograde fifths of a second chronograph (1 column wheel)
34. Retrograde fifths of a second rattrapante chronograph (1 column wheel)
35. 12-hour counter (1 column wheel)
36. 60-minute counter
Alarm Functions
37. Progressive alarm with single gong and hammer striking
38. Alarm strike / silence indicator
39. Choice of normal alarm or carillon striking alarm indicator
40. Alarm mechanism coupled to the carillon striking mechanism
41. Alarm striking with choice of grande or petite sonnerie
42. Alarm power-reserve indication
Westminster Carillon Striking Functions
43. Carillon Westminster chiming with 5 gongs and 5 hammers
44. Grande sonnerie passing strike
45. Petite sonnerie passing strike
46. Minute repeating
47. Night silence feature (between 22.00 and 08.00 hours hours chosen by the client)
48. System to disengage the striking barrel when fully wound
49. Indication for grande or petite sonnerie modes
50. Indication for silence / striking / night modes
Further functions
51. Power-reserve indication for the going train
52. Power-reserve indication for the striking train
53. Winding crown position indicator
54. Locking mechanism for the striking
55. Winding system for the double barrels
56. Hand-setting system with two positions and two directions
57. Concealed flush-fit winding crown for the alarm mechanism
CALENDARS
The most complicated watch ever made by Vacheron Constantin, a custom-made creation gives pride of place to calendars. Echoing the complexity so powerfully staged in the Reference 57260 watch, that involved in creating and using calendars to mark the rhythms of human life dates back to the dawn of civilization.
The calendar is fundamentally based upon the seasons, equinoxes, and the cycles of the sun and moon. Even today, there are several different calendars in use in various cultures throughout the world which differ from the most widely used Gregorian calendar. For instance, Chinese, Islamic, Zoroastrian, Hebrew and Hindu calendars are calibrated to determine particular religious festivals or annual natural events. All are essentially based upon either the cycle of the sun (solar calendar), the moon (lunar calendar), or a combination of both (lunisolar calendar). Naturally, the calculations for determining calendars are very important in watchmaking, especially in the construction of accurate perpetual calendar mechanisms made to function sometimes for centuries without manual adjustment. In watches displaying astronomical and seasonal indications that are integrally linked to a calendar mechanism, the calculations made by the watchmaker are incredibly complex but may result in a mechanism that can self-correct for almost every known eventuality far into the future. To understand how the calendar is translated into a mechanical function and display on a watch, it is necessary to understand which calendar formula is used and the differences between the various calendar types, each with their own particular anomalies. In certain circumstances, especially where a calendar has to be calculated in the extreme long term or for a specific purpose, it may be mathematically desirable to base a mechanical calendar solely on either the lunar (moon) cycle or the lunisolar and Metonic (19-year) cycle. These cycles can give more accuracy in the very long term, but require their own compensatory systems to be built in so as to allow synchronization with the more standard solar calendar.
The Gregorian Calendar
In modern times, the most widely used calendar is the Gregorian calendar, a tropical solar calendar named after its founder, Pope Gregory XIII who introduced it in 1582 as a reform of the Julian calendar which had been used in Europe since its introduction by Julius Caesar in 46 BC. The reason for the reform was that the Julian calendar drifted over time so that eventually the celebration of Easter, tied to the spring equinox, was out of sync with the season in which it occurred. The practical effect of Gregory's reform meant that the number of leap years was reduced from 100 to 97 in every 400 years. Every year that is exactly divisible by four is a leap year, except for years that are exactly divisible by 100, but these centurial years are leap years if they are exactly divisible by 400. For example, the years 1700, 1800, and 1900 are not leap years, but the year 2000 is. The adoption of the Gregorian calendar regularized the anomalies of the old Julian calendar resulting in a calendar that accurately indicates the seasons and runs from January 1st to December 31st with 365 days and the year divided into 12 months. In a leap year, a leap day is added to February, this is known as "intercalation", the added day being "intercalary". The Gregorian calendar is now in everyday use in most parts of the world as the accepted standard calendar. However, being solar, its dates do not indicate the phases of the moon.
The Solar Calendar
The solar calendar is the basis of the majority of commonly used calendars including the Gregorian calendar, because it gives a year comprising 365 days (exactly 365.2425 days). It is calculated by the position of the earth in its orbit around the sun in respect to the equinox, the point at which the orbit crosses the celestial equator. This means that its dates accurately indicate the seasons synchronized with the sun's declination its position on the horizon.
The solar calendar became widely adopted because of its relative stability and ease of use for civil purposes and as a reliable guide to cyclical natural events and annual established religious festivals. Being solely derived from the position of the earth in orbit of the sun, it does not indicate the dates of moon phases. Where both solar and lunar indications are required, the "lunisolar" calendar can be used.
The Lunar Calendar
As the name suggests, the lunar calendar is calculated on the phases of the moon and unlike the solar calendar is not linked to the seasons. Even though the solar-based Gregorian calendar is in common use, the lunar calendar is still used to determine national holidays in many parts of Asia such as Ramadan, Chinese New Year and Mongolian New Year. An example of a purely lunar calendar is the Islamic calendar the official calendar of Saudi Arabia, which has 12 lunar months with a total of 354.37 days in a year. The pure lunar calendar can therefore be up to 12 days adrift from a solar year, only returning to synchronicity every 33 years. The start of a lunar month also differs from culture to culture: it can be when the new moon occurs, or the day after the new moon. In the Hebrew calendar the first day of the month was based on the first sighting of a lunar crescent. The average length of a lunar month is 29.530589 days but for convenience a system of alternating months of 29 and 30 full days is used in order to construct a lunar calendar. An extremely complex calculation, using continued fractions and thus examining the length of the month in terms of fractions of a day, determines which months are 29 or 30 days. The lunar calendar in isolation is, except in rare specific instances and countries, impractical as a calendar for everyday use because it depends on human observations that are uncertain and of course dependent on weather conditions. However, it forms an integral part of any advanced calendar system and in watchmaking is the basis of the calculations for more advanced moon phase indications. When the lunar calendar is coupled with aspects of the solar calendar it can be brought into annual synchronisation and is then termed "lunisolar".
The Lunisolar Calendar
A lunisolar calendar is a combination of aspects of the lunar and solar calendars in which both the time and season of the solar year and the phases of the moon are indicated. This is useful where the solar calendar is of primary importance, but also where events are affected by lunar cycles, for example to determine the date of Easter or other religious dates or to predict natural events occurring at specific periods in the moon's cycle. The lunisolar calendar is therefore the most useful and accurate calendar for very sophisticated applications. The months in the lunisolar calendar follow the moon's cycle but must also be aligned with the seasons in the solar year which are governed by the sun, hence "lunisolar". Lunar months have a duration of 29 ½ days and therefore 12 lunar months are not equal in length to a solar year but instead total 354 days, around eleven days shorter each year. If no adjustment were made, the dates would quickly lose synchronicity with the seasons and fixed events would subsequently occur in the wrong seasons. The solution is to insert a further "thirteenth" intercalary or additional month about every three years which compensates for all the lunar calendar's lost days. This sequence is calculated using the Metonic cycle to which it is inextricably linked.
The Metonic Cycle
Implemented by the ancient Babylonians around 500 BC, the Metonic cycle is a period of nineteen years which the Greek astronomer Meton reported around 432 BC as remarkably being an almost exact multiple of the solar year and the lunar month. In a period of nineteen years there are 235 lunar months equalling 6,940 days. The difference between nineteen solar years and 235 lunar months is only about two hours, therefore the Metonic cycle's error is only one full day every 219 years and as such it is extremely accurate. Meton's calculations of the cycle were very significant in allowing a reliable calculation of the lunisolar calendar providing the knowledge of when the thirteenth intercalary month should be added to keep the lunar year in pace with the solar year and thus maintaining the seasons at the same calendar times each year. Before this the question of when to add a month was decided unscientifically by an official. Meton realised that the thirteenth month had to be added on seven occasions during each consecutive nineteen-year period: in years 3, 6, 8, 11, 14, 17 and 19. The cycle can be used to predict eclipses, calculate the date of Easter and also forms the basis of the Greek and Hebrew calendars.
More remarkably, the Metonic cycle appears to be entirely coincidental because the periods of the Moon's orbit around the Earth and the Earth's orbit around the sun are believed to be independent and have no known physical resonance other than with each other.
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