Chronograph

A chronograph is a specific type of watch that is used as a stopwatch combined with a display watch. A basic chronograph has an independent sweep second hand; it can be started, stopped, and returned to zero by successive pressure on the stem. Less simple chronographs use additional complications and can have multiple independent hands to measure seconds, minutes, hours and even tenths of a second. In addition, many modern chronographs use moveable bezels as tachymeters for rapid calculations of speed or distance. Louis Moinet invented the chronograph in 1816 for use in tracking astronomical objects. Chronographs were also used heavily in artillery fire in the mid to late 1800s. More modern uses of chronographs involve piloting airplanes, car racing, diving and submarine maneuvering.

The term chronograph comes from the Greek word for time, "chronos", combined with the Greek word for writing, "graph". Early versions of the chronograph are the only ones that actually used any "writing": marking the dial with a small pen attached to the index so that the length of the pen mark would indicate how much time has elapsed. The first modern chronograph was invented by Louis Moinet in 1816, solely for working with astronomical equipment. It was Nicolas Mathieu Rieussec who developed the first marketed chronograph at the behest of King Louis XVIII in 1821. The King greatly enjoyed watching horse races, but wanted to know exactly how long each race lasted, so Rieussec was commissioned to invent a contraption that would do the job: as a result he developed the first ever commercialized chronograph. Rieussec was considered the inventor of the chronograph until the Louis Moinet pocket chronograph discovery in 2013 when history was rewritten.

In 1844 Adolphe Nicole's updated version of the chronograph was the first to include a re-setting feature which now allowed successive measurements, unlike the constantly moving needle in the original chronograph.

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.

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