One theme I like is early Chronometers. 1940’s – 1960’s Chronometers I really find them interesting since that is the period where brands started to make “mass produced” Chronometers.
Before that you can find Chronometers, but often created as one off or in very small series.
From the 1940’s and onwards the movement precision and manufacture technic made it possible to make larger series of watches certified as Chronometer which were sold on the open market.
One of these Chronometers which were series produced with great success was the Girard-Perregaux reference 8795 Gyromatic Chronometer HF!
HF standing for High Frequency which applies to the legendary GP Calibre 32A.
In 1967 Girard-Perregaux submitted 662 watches to the Neuchatel Observatory which all passed the Chronometer test. 73% of all watches that year which passed the test!
Watches with Astronomical Observatory certification were now available for a much wider public.
The movement used were the improved GP Calibre 32A based on the Calibre AS 1738B. A high frequency movement, 36.000 vph (5 Hz).