The term “Chronometer” (from ancient Greek chrónos “time” and métron “measure, measuring stick”) indicates highly precise watches. In the past, these were needed for timing and navigation on vessels and aircrafts.
The Swiss movement of a watch must pass a 15-day endurance test (in accordance with NIHS 95-11 / ISO 3159) conducted by the independent Swiss observatory Contrôle officiel suisse des chronomètres (COSC), in order for it to be entitled to use the name official chronometer. Before the COSC’s founding in 1973, the audit was performed by various private and semigovernmental laboratories.
If the movement receives the COSC certificate, the manufacturer usually labels the watch with the word “Chronometer” or the French “Chronomètre”. After passing the test, the movement receives a certificate which validates its accuracy rating.
In 1916, for the first time, watches from the factory of the Kurth brothers were sent to Biel to the “Bureau Officiel de Contrôle de la Marche de Montres” and were successfully tested. But before 1960, fewer than 500 watches with COSC certificate were sold. I guess they all had the 28-45 movement inside. From 1960 to 1971, only 8821 mechanical chronometers were produced at Certina. All with the 25-65 movement (without date) or 25-651 (with date). The movement has a unique serial number which must match the one on the case back.
Not surprisingly, these models are hard to find nowadays. In comparison, this makes any chronometer model, for example, from Omega or Rolex seem like a mass-production item.
The following list contains only models with mechanical movements.
| Model | Reference no. | Calibre | Dimensions mm | Comments | |
|---|---|---|---|---|---|
 |
Certina – Kurth Freres Chronometer Automatic |
28024 9 | Certina 28-45 | D: 33.0 H: 10.0 |
Automatic. Sweep second. No date. Case 14kt. yellow gold About 1955 |
 |
Town and Country Chronometer Automatic | 5880 116 | Certina 25-651 | 30.5 x 30.5 w/o lugs H: 10.5 |
Date without quickset. Monoshell case 18kt. yellow gold From 1965 to 1970 |
 |
Chronometer Automatic | 5801 200 | Certina 25-651 | D: 35.0 H: 11.0 LW: 18 |
Date without quickset. “Officialy Certified Chronometer” on back From 1966 to 1970 |
 |
Chronometer Automatic | 5827 200 | Certina 25-651 | D: 35.0 H: 11.0 LW: 18 |
Date without quickset. “Officially Certified Chronometer” on back Steel case with goldcap. From 1966 to 1970 |
|
Chronometer Automatic | 5880 200 | Certina 25-651 | D: 35.0 H: 11.0 LW: 18 |
Date without quickset. “Officialy Certified Chronometer” on back Case 18kt. yellow gold. Dial silver or gold. From 1966 to 1970 |
 |
DS-2 Automatic Chronometer | 5880 300 | Certina 25-651 | 38.5 x 42 x 12 LW: 18 |
Date without quickset. Bracelet, case and dial in 18 carat yellow gold From 1968 to 1975 |