A chronograph is a type of watch which is a stopwatch combined with a standard watch. A basic chronograph has hour and minute hands on the main dial to tell the time, a small seconds hand to tell that the watch is running, and a seconds hand on the main dial (usually equipped with a sweeping movement for precision) accompanied by a minutes sub dial for the stopwatch. Another sub dial to measure the hours of the stopwatch may also be included on a 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.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. Louis Moinet invented the chronograph in 1816 for use in tracking astronomical objects. Chronographs soon found use in artillery fire in the mid to late 1800s, and over times became fixtures in fields as diverse as aircraft piloting, auto racing, diving and submarining.
Since the 1980s, the term chronograph has also been applied to all digital watches that incorporate a stopwatch function.
