A chronometer is a highly accurate timekeeping device, often used in navigation and scientific research. It is designed to maintain precise time over long periods, which is essential for determining longitude at sea. The invention of the chronometer in the 18th century significantly improved maritime navigation. Chronometers are typically mechanical or electronic and are known for their reliability and precision. They undergo rigorous testing to ensure they meet strict standards set by organizations like the COSC (Contrôle Officiel Suisse des Chronomètres). This certification guarantees that the chronometer can keep time within a few seconds per day.