Observatory chronometer

An observatory chronometer is a timepiece that has passed stringent testing and a slate of accuracy tests. Thus, the "observatory trial" developed as the standard process for determining accuracy of timepiece movements. If the chronometer passed the stringent testing, it would be certified.

In the world of mechanical timepieces, accuracy is paramount. In the times before electronics, mechanical timepieces called marine chronometers were developed to a very high degree of accuracy for use in maritime navigation. To test the accuracy of such marine chronometers, watchmakers looked to a phalanx of astronomical observatories located in Western Europe to conduct assessments of timepieces.