kronographs

A chronograph is a type of watch that includes a stopwatch function. This means it can measure elapsed time independently of the main timekeeping function. The stopwatch mechanism is typically operated by one or more pushers on the side of the watch case. These pushers control the start, stop, and reset functions of the chronograph's hands. The chronograph's dial usually features sub-dials that display the elapsed seconds, minutes, and sometimes hours. The primary chronograph hand is often a central sweep seconds hand that moves only when the stopwatch is engaged.

The invention of the chronograph dates back to the early 19th century, with various watchmakers contributing to its development. Early chronographs were primarily used for scientific purposes and racing. Over time, they became popular with pilots, military personnel, and athletes, valued for their ability to precisely measure time intervals. Modern chronographs can range from simple timekeeping devices with an added stopwatch to complex mechanical movements with numerous complications. The mechanism behind a chronograph involves a series of wheels, levers, and springs that engage and disengage to control the stopwatch functions. The complexity and precision of these movements can vary significantly between different models and manufacturers.