In the days before Switzerland’s COSC became the ubiquitous standard for chronometer certifications, several independent observatories throughout Europe evaluated watch movements and bestowed their own certificates. Switzerland’s Neuchâtel and Geneva Observatories are two very well-known examples. In France, it was Besançon’s Observatory, just over the border from the Swiss watchmaking centers of Le Locle, Neuchâtel, and La Chaux-de-Fonds. England’s Kew Observatory, affiliated with the Greenwich Observatory, was among the most famous, and was responsible for certifying marine chronometers that were supplied to the Royal Navy. In its time, Kew employed a far more rigorous chronometer testing regime than those used elsewhere. While 15 days of testing was the standard across most observatories, Kew went further, and tested watches for 44 days, in a range of positions, and at various temperatures. The movements that obtained the best results were designated “Kew A.”
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