Neuchâtel Observatory Trials 1966-1970

Observatoire Cantonal de Neuchâtel opened in 1860. Picture credit: wikipedia

Chronometer trials in general are a method for the watch industry to objectively verify and certify the precision of their manufactured pieces. Such trials were performed at astronomical observatory facilities, as they had the most precise ‘mother’ timepieces which served as reference for determining the precision of the submitted candidates.

After over a century of serving as testing facility for marine chronometers and other mechanical precision timepieces, the observatory of Neuchâtel served also as test facility during the development of the quartz watches.

The Beginning of a New Era

Already in 1966 a newly developed ‘wristwatch with acoustic frequency‘ has annihilated the mechanical concurrence establishing a new precision record N = 1.64 (0 being the virtually best possible value, suggesting absolute precision) (1). This watch was driven by a modified Bulova ‘Accutron‘ movement, which was developed by Ebauches SA and named ‘MOSABA; MOvement SAns BAlancier‘ or movement without balance wheel. Similar modified Accutron versions, named ‘Swissonic‘ were submitted by CEH, where the newly recruited Max Hetzel (the inventor of the ‘Accutron‘ movement) was intended to help the Swiss watch industry to gain terrain for the development of an all Swiss electronic watch (2).

A New Definition of Precision

In preview of protests coming from manufacturers of traditional mechanical watches, new categories for the chronometer competition were introduced for 1967. So the category for ‘quartz wristwatches‘ was added to the already newly introduced category for the ‘wristwatches with acoustic frequency‘ introduced the year before.

As expected the quartz prototypes submitted by the CEH in 1967 pulverised all records and took the first 10 places with a precision range of N = 0.152 – 0.292, the winner being 12 times more precise than the 1966 winner (3).

Radical Decision and Re – Orientation

The results of the chronometer competition of 1967 had an immense impact on the process. As it was expected that the quartz watches would get even more precise, the very purpose and existence of a chronometer competition was questioned (4).

In 1968 the competition for wrist watches was cancelled and a special task force was created by the observatory, which should evaluate a complete change of parameters and regulations of such measurements for wrist watches and establish a ‘new competition‘ for the following years (4). The following new principles and changes would apply:

Organisation: two groups would be distinguished: prototypes and a selection of production watches

Engineering: Abolition of size limitations for wrist watches (before: diameter equal or < 30mm or surface equal or < 707 mm2, maximum thickness: 5.3mm (3)). The introduction of dynamic tests. Only testing in a purely experimental setting was performed before, but the watch industry understood, that wrist watches should be tested also in ‘simulated dynamic scenarios’. So the watches would be tested at higher temperature (65c), be submitted to shocks (100g), linear and angular acceleration (3g) and exposed to a magnetic field (60Oe) (4).

This new preliminary protocol was tested during three sessions from November 1968 to December 1969. These testing phases permitted to construct and acquire new testing devices for wrist watches. 80 prototype watches provided by 4 watch manufacturers served as experimental pieces to test the new devices. As amendment to the new protocol, decided by the task force in accordance with representatives of the Swiss watch industry, the test period for the watches was reduced from 45 to 38 days and the results would not be public anymore, but sent directly to the respective manufacturers, for them to decide upon publication. Latter change was well received by the Swiss watch industry, as the results of less performing watches would not be made public and thus would not potentially compromise their sales (5).

Because of the introduction of the new criteria for testing wristwatches, the focus shifted to the technical performance of the watches neglecting the competitive and commercial aspects. With the loss of the competition aspect, also many of the prizes issued for the engineers, such as the ‘Prix Guillaume’, were canceled. In view of the excellent feedback from the Swiss watch industry, the testing parameters of watches of all other categories would be adapted to the new protocol for the chronometer measurements starting from 1970 (5).

The new chronometer measurement protocol for all watches was officially introduced by decree by the Canton of Neuchâtel the 20.02.1970. This new protocol would be tested further until the 31.12.1972 and then reevaluated (6).


  1. Observatoire Cantonal de Neuchâtel, Rapport sur le concurs chronométrique, 1966
  2. Trueb L. F., Ramm G., Wenzig P.; Die Elektrifizierung der Armbanduhr; Ebner Verlag, 2011
  3. Observatoire Cantonal de Neuchâtel, Rapport sur le concurs chronométrique, 1967
  4. Observatoire Cantonal de Neuchâtel, Rapport sur le concurs chronométrique, 1968
  5. Observatoire Cantonal de Neuchâtel, Rapport sur le concurs chronométrique, 1969
  6. Observatoire Cantonal de Neuchâtel, Rapport sur le concurs chronométrique, 1970