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 and a minute sub-dial; it can be started, stopped, and returned to zero by successive pressure on the stem. More complex chronographs use additional complications and can have multiple sub-dials to measure seconds, minutes, hours and even fractions 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 aircraft piloting, auto racing, diving and submarine maneuvering. Since the 1980s, the term chronograph has also been applied to all digital watches that incorporate a stopwatch function. History The term chronograph comes from the Greek ( 'time recording'), from ( 'time') and ( 'to write'). 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 had 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 addition to inventing the chronograph, Louis Moinet is also the father of High Frequency. In 1816, his Compteur de Tierces timepiece beat at a rhythm of 216,000 vibrations per hour (30 Hz). This frequency record stood for exactly one century, before eventually being broken in 1916 – after which standard chronometer frequencies returned to present-day levels (generally 4-5 Hz). Still in perfect working order, the Compteur de Tierces is preserved at Ateliers Louis Moinet. In 1915, Gaston Breitling produced the first chronograph with a central seconds hand and a 30-minute counter. Later, in 1923, Gaston Breitling introduced