Watchbazar has been asked often about the difference between chronograph and chronometer lets try to explain .
The term, Chronograph comes from the Greek word for time, “chronos”, combined with the Greek word for writing, “graph”. Early versions of the chronograph are the only ones that actually used any “writing”: marking the dial with a small pen attached to the index so that the length of the pen mark would indicate how much time has elapsed.
The first modern chronograph was invented by Louis Moinet in 1816,solely for working with astronomical equipment. It was Nicolas Mathieu Rieussec who developed the first marketed chronograph at the behest of King Louis XVIII in 1821. The King greatly enjoyed watching horse races, but wanted to know exactly how long each race lasted, so Rieussec was commissioned to invent a contraption that would do the job: as a result he developed the first ever commercialized chronograph.
In 1844 Adolphe Nicole’s updated version of the chronograph was the first to include a re-setting feature which now allowed successive measurements, unlike the constantly moving needle in the original chronograph
In the early part of the 20th Century many chronographs were sold with fixed bezels marked in order to function as a tachymeter . In 1958 the watch company Heuer introduced a model with a rotating bezel tachymeter for more complex calculations.
Chronographs were very popular with aviators as they allowed them to make rapid calculations and conduct precise timing. The demand for chronographs grew along with the aviation industry in the early part of the 20th century. As the US exploration of outer space initially involved only test pilots, by order of President Eisenhower, chronographs were on the wrists of many early astronauts.
A ‘Seiko automatic Chronograph’ Cal. 6139, the Pogue Seiko, the first automatic chronograph in space
Appella Chronograph equipped with a self-winding mechanical Valjoux 7750 movement. 30-minute and 12-hour counters
The term chronometer is a specific type of timepiece tested and certified to meet certain precision standards. In Switzerland, only timepieces certified by the Contrôle Officiel Suisse des Chronomètres (COSC) may use the word ‘Chronometer’ on them. Outside Switzerland, equivalent bodies (such as the Japan Chronometer Inspection Institute) have in the past certified timepieces to the same internationally recognised standards, although use of the term has not always been strictly controlled.
The term chronometer was coined by Jeremy of Beverly, England in 1714, referring to his invention of a clock ensconced in a vacuum chamber. The term chronometer is also used to describe chronometer used for celestial navigation and determination of longitude. The marine chronometer was invented by John Harrison in 1730. This was the first of a series of chronometers that enabled accurate marine navigation. From then on, an accurate chronometer was essential to deep sea marine or air navigation out of sight of land. Early in the Twentieth Century the advent of radiotelegraphy time signals supplemented the onboard marine chronometer for marine and air navigation, and various radio navigation systems were invented, developed, and implemented during and following the 2nd World War
More than 1,000,000 Officially Certified Chronometer certificates, mostly for mechanical wrist-chronometers with sprung balance oscillators, are being delivered each year, after passing the COSC’s most extreme tests and being singly identified by an officially recorded individual serial number. According to COSC, a chronometer is a high precision watch capable of displaying the seconds and housing a movement that has been tested over several days, in different positions, and at different temperatures, by an official, neutral body (COSC). Each movement is individually tested for several consecutive days, in five positions and at three temperatures. Each movement is individually measured. Any watch with the denomination “chronometer” contains a certified movement.
REMEMBER: Chronometer and Chronograph are separate terms, but a chronograph can be a chronometer if it passes the requisite tests.