A chronograph is a type of watch that functions as both a display watch and a stopwatch. It typically features hour and minute hands on the main dial, a small seconds hand to indicate the watch is running, and a seconds hand with a sweeping movement for precision. This is often accompanied by a minutes sub-dial for the stopwatch function. Some chronographs also include an additional sub-dial to measure the hours of the stopwatch. The stopwatch can be started, stopped, and reset to zero using pushers located near the crown. More complex chronographs may include additional complications, such as multiple sub-dials for measuring fractions of a second, moon phases, and local 24-hour time. Many modern chronographs also feature tachymeters on the bezels for quick calculations of speed or distance. The chronograph was invented by Louis Moinet in 1816 for tracking astronomical objects and has since been used in various fields, including aviation, auto racing, diving, and submarine maneuvering.