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6:00 o'clock up
3:00 o'clock up
9:00 o'clock up
Dial down
Dial up
The watch is also tested at 3
different temperatures:
8°
Centigrade
( 46.4° Fahrenheit)
23° Centigrade ( 73.4° Fahrenheit)
38° Centigrade (100.4° Fahrenheit)
It is often quoted that to pass certification the
watch must have a mean daily rate of a minimum of -4 seconds and a
maximum of +6 seconds.
It is actually much more complicated than this simplistic guideline.
Larger calibers would produce
better results than smaller calibers because
the larger parts could be manufactured more precisely than smaller
parts.
The COSC Observatory in
Geneva had 4 testing categories:
1. Deck chronometers between 43 and 70 mm.
2. Pocket chronometers between 38 and 43 mm.
3. Pocket chronometers less than 38 mm.
4. Chronometer wristwatch
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