Greenwich Mean Time

Greenwich Mean Time (GMT) is the mean solar time at the Royal Observatory in Greenwich, London. GMT was formerly used as the international civil time standard, now superseded in that function by Coordinated Universal Time (UTC). Today GMT is considered equivalent to UTC for UK civil purposes (but this is not formalized) and for navigation is considered equivalent to UT1 (the modern form of mean solar time at 0° longitude); these two meanings can differ by up to 0.9 s. Consequently, the term GMT should not be used for precise purposes.

Because of Earth's uneven speed 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 the sky there. This event may occur up to 16 minutes before or after noon GMT, a discrepancy calculated by the equation of time. Noon GMT is the annual average (i.e., "mean") moment of this event, which accounts for the word "mean" in "Greenwich Mean Time".

Rolex GMT Master II

The Rolex Oyster Perpetual Date GMT Master is part of the Rolex Professional Watch Collection. Designed in collaboration with Pan American Airways for use by their pilots and navigators, it was launched in 1954.

History

The Rolex GMT-Master wristwatch was originally designed in collaboration with Pan American Airways and issued by the airline to their crews on long-haul flights. ("GMT" in the name stands for Greenwich Mean Time now known as Coordinated Universal Time). The original GMT Master watch has a 24-hour display fourth hand complication directly linked to and displaying 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. Among known characters, Fidel Castro and Che Guevara wore a Rolex GMT Master.

Rolex

Rolex SA and its subsidiary Montres Tudor SA design, manufacture, distribute and service wristwatches sold under the Rolex and Tudor brands. Founded by Alfred Davis and Hans Wilsdorf in London, England in 1905 as Wilsdorf and Davis, Rolex moved its base of operations to Geneva, Switzerland in 1919.

Forbes ranked Rolex No.72 on its 2014 list of the world's most powerful global brands. Rolex is the largest single luxury watch brand, producing about 2,000 watches per day, with estimated 2012 revenues of US$7.7 billion.

The company is owned by the Hans Wilsdorf Foundation, a family private trust which does not pay corporate tax.

History

Alfred Davis and his brother-in-law Hans Wilsdorf founded Wilsdorf and Davis, the company that would eventually become Rolex SA, in London, England in 1905. Wilsdorf and Davis' main commercial activity at the time involved importing Hermann Aegler's Swiss movements to England and placing them in high-quality watch cases made by Dennison and others. These early wristwatches were sold to jewellers, who then put their own names on the dial. The earliest watches from Wilsdorf and Davis were usually hallmarked "W&D" inside the caseback.

Miles Master

The Miles M.9 Master was a British 2-seat monoplane advanced trainer built by Miles Aircraft Ltd for the Royal Air Force and Fleet Air Arm during the Second World War. It went through a number of variants according to engine availability and was even modified as an emergency fighter during the Battle of Britain. It was a fast, strong and fully aerobatic aircraft and served as an excellent introduction to the high performance British fighter aircraft of the day: the Spitfire and Hurricane.

Design and development

The M.9A Master I was based on the M.9 Kestrel trainer that was first demonstrated at the Hendon Air show in July 1937, although it never entered production. The M.9 Kestrel, powered by the 745 hp (555 kW) Rolls-Royce Kestrel XVI V-12 engine, could reach 296 mph (477 km/h). The Air Ministry had selected the de Havilland Don as its advanced trainer, but this proved to be a failure, and the RAF placed a £2 million order for 500 examples of a modified version of the Kestrel, the M.9A Master. Miles rebuilt the prototype M.9 to form a prototype for the Master, fitting a lower powered (715 hp (535 kW)) Rolls-Royce Kestrel XXX engine, of which there were large surplus stocks available, and with extensive revisions to the airframe, which included a new cockpit canopy, a modified rear fuselage and tail, and moving the radiator from under the nose to under the centre-section of the wing. These modifications significantly reduced the aircraft's speed, but it remained one of the fastest and most maneuverable trainers of its day. The first true production Master I made its maiden flight on 31 March 1939. The Master entered service just before the start of the war, and eventually 900 Mk. I and Mk. IA Masters were built. This total included 26 built as the M.24 Master Fighter which were modified to a single-seat configuration, and armed with six .303 in machine guns for use as an emergency fighter, but did not see combat.

Rolex Submariner

The Rolex Oyster Perpetual Submariner is a line of sports watches designed for diving manufactured by Rolex, known for their resistance to water and corrosion. The first Submariner was introduced to the public in 1954 at the Basel Watch Fair. The Rolex Submariner is considered "a classic among wristwatches", manufactured by one of the most widely recognized luxury brands in the world, and due to its popularity has become the subject of massive counterfeiting. The Rolex Submariner is part of Rolex's Oyster Perpetual line.

Early models

The Submariner model went into production in 1953 and was showcased at the Basel Watch Fair in 1954. The assigned case reference number of this first Submariner was either 6204 or 6205. It is unclear which model came first; in any event, the two watches are nearly identical. Neither has the distinctive "cathedral" or "Mercedes" hands now so strongly associated with the Submariner line. Rather, both of these early submariners have straight "pencil" style hands. Few, if any, of the 6205 watches bear the name "Submariner" on the dial, a major distinction of modern Submariners. Some 6204 models have the Submariner logo printed below the center pinion, while others have the logo blacked out. It is believed that there were unexpected trademark issues connected with the name "Submariner" at the time the 6204 and 6205 were released, accounting for the inconsistent use of the Submariner mark on these early Submariners. Trademark irregularities notwithstanding, both the 6204 and 6205 are designated Submariner models in Rolex product literature.