The chronograph is a timepiece which shows the time to which is added a mechanism enabling the length of an event to be measured. The chronograph hand is generally placed in the centre of the dial. When the push-buttons located on the middle part of the case are actuated, it can be started, stopped and brought back to its point of departure. It completes one revolution in one minute. Small counters on the dial total the minutes and hours. The chronograph is the outcome of a long series of successive contributions and improvements which, little by little, brought this idea born in the 18th century to fruition.
Over time, the chronograph counter was enriched by a number of innovations :
The split-seconds chronograph enables intermediate times to be read. A second seconds hand, known as the split-seconds hand, is positioned over the chronograph hand. Perfectly superimposed and synchronised, the two hands rotate together. When the user wishes to determine an intermediate time without interrupting the measurement, the split-seconds hand is stopped by pressing the pushpiece. When further pressure is applied, this hand rapidly “catches up” with the chronograph hand.
The jumping seconds hand, also known as a diablotine, enables fractions of a second to be read more easily. The jumping hand completes one rotation every second, during which it stops five times (or four depending on the frequency of the balance-spring assembly).
The chronograph with a flyback function enables a new timing process to be launched while the first is already under way by pressing a single pushpiece.
Then there is the case of regatta watches, equipped not only with a chronograph but also with a countdown function. Some watches enable a countdown in a range of between 1 and 10 minutes to be programmed. Others incorporate a five minute countdown function which allows the time until the race start to be determined.