Standards and methods
Each officially certified COSC chronometer is identified by a serial number engraved on its movement and a certification number given by the COSC.
Testing criteria are based on ISO 3159[9] which defines a wrist chronometer with spring-balance oscillator. Only movements which meet the precision criteria established under ISO 3159 are granted an official chronometer certificate. Compare ISO 3158.[10]
Each uncased movement is individually tested for fifteen days, in five positions, at three different temperatures. The movements are fitted with a seconds hand and the automatic winding mechanisms are disengaged for the tests. Measurements are made daily with the aid of cameras. Based on these measurements, seven eliminatory criteria are calculated, each of which must be met e.g. for movements of a diameter over 20 mm, the requirements, indicated in seconds/day, are noted in the table below. There is no ISO standard for quartz timepieces, but there is development in this field. ISO 10553:2003 specifies the procedure for evaluating the accuracy of quartz watches, individually and by lot, and the relationship between the accuracy tested and the accuracy classification given by the manufacturer. It applies to quartz watches having accompanying documents on which the accuracy classification is indicated. Nevertheless, COSC has also developed its own standard for testing quartz chronometers with eight eliminatory criteria, also noted in the table below.
COSC Standards
Mechanical Quartz
Average daily rate: -4/+6 [11] Average daily rate at 23 °C: ± 0.07
Mean variation in rates: 2 [12] Rate at 8 °C: ± 0.2
Greatest variation in rates: 5 [13] Rate at 38 °C: ± 0.2
Difference between rates in H & V positions: -6/+8 [14] Rate stability: 0.05
Largest variation in rates: 10 [15] Dynamic rate: ± 0.05
Thermal variation: ± 0.6 [16] Temporary effect of mechanical shocks: ± 0.05
Rate resumption: ± 5 [17] Rate resumption: ± 0.05
n/a Residual effect of mechanical shocks: ± 0.05;
200 shocks equivalent to 100 G (981 m/s², 3,217 ft/s²)
Measurements are compared with a time base established by two independent atomic clocks synchronized on GPS time. Not all chronometers are supplied with the report issued by the COSC as the reports are optional to the brand or maker. Each manufacturer may decide whether to reveal the results gathered during the certification process of the movement. For example, Breitling do supply all their watches with COSC Certificates (all Breitling watches since 2000 are Certified chronometers) however Rolex and Omega do not supply even their chronometer certified watches (not all their watches are certified chronometers) with the COSC certificates. Omega however can provide the COSC chronometer certificate if asked.
Antiguos Moderadores
(es una broma, eh?). Sobre el hilo y Paneristi, si se quiere modificar o cerrar no hay ningún problema. Mi enfado era porque no me responden los moderadores y no se me permite aclararlo, nada más.
y lo tuve que devolver, tras varios días encontraron el mío me lo mandaron 
, desde luego ya no he vuelto a comprar nada allí...
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