Chronograph
The stopwatch can be started, stopped, and reset to zero at any time by the user by operating pushers usually placed adjacent to the crown.
[1] More complex chronographs often use additional complications and can have multiple sub-dials to measure more aspects of the stopwatch such as fractions of a second as well as other helpful things such as the moon phase and the local 24-hour time.
In addition, many modern chronographs include tachymeters on the bezels for rapid calculations of speed or distance.
Over time, the chronograph found its use to be in several different fields, such as aircraft piloting, auto racing, diving and submarine maneuvering.
The term chronograph comes from the Greek χρονογράφος (khronográphos 'time recording'), from χρόνος (khrónos 'time') and γράφω (gráphō 'to write').
It was Nicolas Mathieu Rieussec who developed the first marketed chronograph at the behest of King Louis XVIII in 1821.
Still in perfect working order, the Compteur de Tierces is preserved at Ateliers Louis Moinet.
[6][14] In the early part of the 20th century, many chronographs were sold with fixed bezels marked in order to function as a tachymeter.
In 1958 the watch company Heuer introduced a model with a rotating bezel tachymeter for more complex calculations.
[15][16] Chronographs were very popular with aviators as they allowed them to make rapid calculations and conduct precise timing.
As the US exploration of outer space initially involved only test pilots, by order of President Dwight D. Eisenhower,[17][18] chronographs were on the wrists of many early astronauts.
Chronograph usage followed a similar trajectory for many fields that involve very precise and/or repeated timing around increasingly more complicated high performance machinery, automobile racing and naval submarine navigation being two examples.
As different uses for the chronograph were discovered, the industry responded with different models introducing such features as the flyback (where the second hand could be rapidly reset to zero), minute and hour timers, Rattrapante (or multiple second hands one of which can be stopped and started independently) and waterproof models for divers and swimmers.
In 1969, the watch companies Heuer, Breitling, Hamilton, and movement specialist Dubois Dépraz, developed the first automatic chronograph in partnership.
They developed this technology secretly in an effort to prevent other watchmaking houses from releasing an automatic chronograph first, namely their competition Zenith and Seiko.
Chronographs are routinely used to record heart beats within hospitals, calculate speed and/or distance on athletic fields, or even as simple timers in kitchens.
The watchmaking company Breitling offers a model with a rotating bezel, in conjunction with another, fixed, meter on the dial, scaled for use as a slide rule for more complex calculations.
[9] A rattrapante, sometimes called a double chronograph, has multiple second hands, at least one of which can be stopped and started independently.
[30] The telemeter chronograph allows the user to approximately measure the distance to an event that can be both seen and heard (e.g. a lightning bolt or a torpedo strike) using the speed of sound.
