The Rolex Oyster Perpetual Date GMT Master is part of the Rolex Professional Watch Collection. Designed in collaboration with the now defunct U.S.-based Pan Am airline for use by their pilots and navigators, it was launched in 1954.
31-501: The Rolex GMT-Master wristwatch was originally designed in collaboration with the Pan American Airways and issued by the airline to their crews on long-haul flights. ("GMT" in the name stands for Greenwich Mean Time , which was later replaced by Coordinated Universal Time (UTC), though the watch kept its name). The original GMT Master watch has a 24-hour display fourth hand complication directly linked to and displaying
62-644: A particular time unless a context is given. The term "GMT" is also used as one of the names for the time zone UTC+00:00 and, in UK law, is the basis for civil time in the United Kingdom. Because of Earth's uneven angular velocity in its elliptical orbit and its axial tilt , noon (12:00:00) GMT is rarely the exact moment the Sun crosses the Greenwich Meridian and reaches its highest point in
93-482: A standard time independent of location. Most time zones were based upon GMT, as an offset of a number of hours (and occasionally half or quarter hours) "ahead of GMT" or "behind GMT". Greenwich Mean Time was adopted across the island of Great Britain by the Railway Clearing House in 1847 and by almost all railway companies by the following year, from which the term railway time is derived. It
124-547: A term introduced in 1928, initially represented mean time at Greenwich determined in the traditional way to accord with the originally defined universal day ; from 1 January 1956 (as decided by the International Astronomical Union in Dublin in 1955, at the initiative of William Markowitz ) this "raw" form of UT was re-labelled UT0 and effectively superseded by refined forms UT1 (UT0 equalised for
155-418: Is able to quickly compute any third time zone reference. Although the original Rolex GMT Master was available only in stainless steel, as it was conceived as a functional work watch, Rolex has been making luxury versions in both mixed steel and gold, and all-gold since the 1950s, and there are even exotic variations that incorporate elaborate designs that include precious stones. An updated Rolex GMT Master II
186-437: Is broadcast to all time zones, the announcers use the term "Greenwich Mean Time" consistently throughout the year. Several countries define their local time by reference to Greenwich Mean Time. Some examples are: Greenwich Mean Time is defined in law as standard time in the following countries and areas, which also advance their clocks one hour (GMT+1) in summer. Greenwich Mean Time is used as standard time all year round in
217-633: Is disseminated to the general public in winter and UTC+01:00 in summer. BBC radio stations broadcast the "six pips" of the Greenwich Time Signal . It is named from its original generation at the Royal Greenwich Observatory . If announced (such as near the start of summer time or of winter time), announcers on domestic channels declare the time as GMT or BST as appropriate. As the BBC World Service
248-791: Is especially used by institutional bodies within the United Kingdom , such as the BBC World Service , the Royal Navy , and the Met Office ; and others particularly in Arab countries, such as the Middle East Broadcasting Centre and OSN . As the United Kingdom developed into an advanced maritime nation , British mariners kept at least one chronometer on GMT to calculate their longitude from
279-446: Is made of Cerachrom, Rolex's patented version of ceramic; it is produced through a patented process of creating two colors out of a mono-block Cerachrom bezel. In 2014, Rolex was able to create the red color on the ceramic bezel for the new incarnation of the red-and-blue "Pepsi", although in order to recoup the higher cost of this bezel it was only initially available on the white gold GMT-Master II. All of these GMT-Master II watches use
310-420: Is much more scratch resistant than aluminum, Rolex initially could not continue to produce the two-color bezel used to distinguish between the day and night times of the second time zone, particularly the color red which could not be created satisfactorily in ceramic. In 2013, Rolex created the first two-tone ceramic bezel, in blue and black, for the steel GMT-Master II nicknamed “Batman”. The blue and black bezel
341-576: Is not strictly defined in material form but from a statistical solution resulting from observations of all time-determination stations which the BIPM takes into account when co-ordinating the world's time signals. Nevertheless, the line in the old observatory's courtyard today differs no more than a few metres from that imaginary line which is now the prime meridian of the world. Historically, GMT has been used with two different conventions for numbering hours. The long-standing astronomical convention, dating from
SECTION 10
#1732780888546372-519: Is the equation of time . Local mean time was used from the early 19th century, when local solar time or sundial time was last used until standard time was adopted on various dates in the several countries. Each town or city kept its own meridian , so locations one degree of longitude apart had times four minutes apart. This became a problem in the mid 19th century when railways needed clocks for railway time that were synchronized between stations, while local people needed to match their clock (or
403-453: The time ball at the observatory redundant. The daily rotation of the Earth is irregular (see ΔT ) and has a slowing trend; therefore atomic clocks constitute a much more stable timebase. On 1 January 1972, GMT as the international civil time standard was superseded by Coordinated Universal Time (UTC) , maintained by an ensemble of atomic clocks around the world. Universal Time ( UT ) ,
434-592: The Caliber 3186 movement. In 2018, Rolex would issue the red-and-blue "Pepsi" on a new steel GMT-Master II, which also has a Jubilee bracelet in lieu of the Oyster bracelet, and it will continue to be sold alongside the older white gold "Pepsi" watch. Two more GMT-Master II models were also introduced, one in red Everose gold and in steel, and another in Everose gold, both with a two-tone brown and black bezel giving them
465-593: The Greenwich meridian, which was considered to have longitude zero degrees, by a convention adopted in the International Meridian Conference of 1884. Synchronisation of the chronometer on GMT did not affect shipboard time, which was still solar time. But this practice, combined with mariners from other nations drawing from Nevil Maskelyne 's method of lunar distances based on observations at Greenwich, led to GMT being used worldwide as
496-427: The Oyster bracelet as an option for both the red-and-blue "Pepsi" and the blue-and-black "Batman" in addition to the existing Jubilee that was released in 2018 and 2019, respectively. This came as quite a surprise for fans, as the original ceramic "Pepsi" came on the Oyster with a black dial, making it an exclusive choice. The only distinguishing feature for the newer white gold model is the blue or meteorite dial, however
527-542: The differences in appearance for the 2014 white gold and the 2021 steel is the movement. Greenwich Mean Time Greenwich Mean Time ( GMT ) is the local mean time at the Royal Observatory in Greenwich , London , counted from midnight . At different times in the past, it has been calculated in different ways, including being calculated from noon ; as a consequence, it cannot be used to specify
558-487: The effects of polar wandering ) and UT2 (UT1 further equalised for annual seasonal variations in Earth rotation rate). Indeed, even the Greenwich meridian itself is not quite what it used to be—defined by "the centre of the transit instrument at the Observatory at Greenwich". Although that instrument still survives in working order, it is no longer in use and now the meridian of origin of the world's longitude and time
589-489: The following countries and areas: Local mean time Local mean time ( LMT ) is a form of solar time that corrects the variations of local apparent time , forming a uniform time scale at a specific longitude . This measurement of time was used for everyday use during the 19th century before time zones were introduced beginning in the late 19th century; it still has some uses in astronomy and navigation. The difference between local mean time and local apparent time
620-489: The name Universal Time was introduced in 1928 to denote GMT as counted from midnight. Today, Universal Time usually refers to Coordinated Universal Time (UTC) or UT1; English speakers often use GMT as a synonym for UTC. For navigation, it is considered equivalent to UT1 (the modern form of mean solar time at 0° longitude); but this meaning can differ from UTC by up to 0.9 s. The term "GMT" should thus not be used for purposes that require precision. The term "GMT"
651-528: The nickname "Root Beer". These new GMT-Master IIs released in 2018 all use the new Caliber 3285 movement which adds Paraflex shock absorber and a 70-hour power reserve (instead of 48 hours) over the Caliber 3186. In 2019, Rolex issued a new version of the Batman, and discontinued the older version. The caliber was upgraded to the Caliber 3285 movement. The bracelet was changed to a Jubilee, which has five-piece links and an Oysterclasp lock. In 2021, Rolex re-issued
SECTION 20
#1732780888546682-471: The same time zone as the standard 12-hour hand. This GMT hand enabled the crews to set the watch to GMT or another time zone, and, using the rotatable 24-hour scale bezel, set to the correct offset, a second time zone could be read. GMT or UTC is the time zone that is required for all aviation planning, weather forecasts, schedules and other paperwork. In the early 1980s the Rolex GMT-Master II
713-409: The sky there. This event may occur up to 16 minutes before or after noon GMT, a discrepancy described by the equation of time . Noon GMT is the annual average (the arithmetic mean ) moment of this event, which accounts for the word "mean" in "Greenwich Mean Time". Originally, astronomers considered a GMT day to start at noon, while for almost everyone else it started at midnight. To avoid confusion,
744-463: The time referred to shall (unless otherwise specifically stated) be held to be Greenwich mean time. Under subsection 23, the same rule applies to deeds and other instruments. During the experiment of 1968 to 1971, when the British Isles did not revert to Greenwich Mean Time during the winter, the all-year British Summer Time was called British Standard Time ( BST ). In the UK, UTC+00:00
775-492: The update is a new and more luxurious style of bracelet that has heavier solid links and a machined clasp. The stainless steel version now joins the precious metal versions by having highly polished centre links on its bracelet. In 2007, Rolex introduced the ceramic bezel insert to the GMT-Master II range, replacing the aluminum insert (colors created using an anodizing process) that had been used since 1959. While ceramic
806-564: The work of Ptolemy , was to refer to noon as zero hours (see Julian day ). This contrasted with the civil convention of referring to midnight as zero hours dating from the Roman Empire . The latter convention was adopted on and after 1 January 1925 for astronomical purposes, resulting in a discontinuity of 12 hours, or half a day. The instant that was designated as "December 31.5 GMT" in 1924 almanacs became "January 1.0 GMT" in 1925 almanacs. The term Greenwich Mean Astronomical Time ( GMAT )
837-620: Was changed later in 1880, when Greenwich Mean Time was legally adopted throughout the island of Great Britain. GMT was adopted in the Isle of Man in 1883, in Jersey in 1898 and in Guernsey in 1913. Ireland adopted GMT in 1916, supplanting Dublin Mean Time . Hourly time signals from Greenwich Observatory were first broadcast by shortwave radio on 5 February 1924 at 17:30:00 UTC, rendering
868-465: Was gradually adopted for other purposes, but a legal case in 1858 held " local mean time " to be the official time. On 14 May 1880, a letter signed by "Clerk to Justices" appeared in The Times , stating that "Greenwich time is now kept almost throughout England, but it appears that Greenwich time is not legal time. For example, our polling booths were opened, say, at 8 13 and closed at 4 13 p.m." This
899-598: Was introduced to unambiguously refer to the previous noon-based astronomical convention for GMT. The more specific terms UT and UTC do not share this ambiguity, always referring to midnight as zero hours . Legally, the civil time used in the UK is called "Greenwich mean time" (without capitalisation), with an exception made for those periods when the Summer Time Act 1972 orders an hour's shift for daylight saving. The Interpretation Act 1978 , section 9, provides that whenever an expression of time occurs in any Act,
930-409: Was released (although production of the original version continued alongside it until 1999). Although the watch looks almost identical it uses a movement that has the additional capability of an independently adjustable quickset hour hand that can be adjusted to local time without stopping the seconds or disturbing the minutes and 24 hour GMT hand. As the watch continues to feature the rotatable bezel it
961-418: Was released in 2005. This new model features a number of technical changes, such as Rolex's patented Parachrom hairspring as well as a larger Triplock crown (from the diver's watches). The new model also has several cosmetic changes, such as larger case, hands and hour markers and also a new bezel made using an extremely hard ceramic material that is designed to be more scratch and fade resistant. Also included in