Power Reserve CERTIFIED CHRONOMETER 18k Gold Antique Pocket Watch

Good French pocket chronometer with power reserve function.
The movement is based on quality LeCoultre ebauche (Calibre 8), but seriously enough modified.
The movement is stamped with Vipère (Viper) hallmark, for the watch obtained Bulletin de Marche of first Class from Besançon Observatory. Typically the accuracy of the watch in this class was within 3 seconds per week.

The Besançon Observatory was created in 1882 as French response for Geneve observatory for purpose of testing timepiece movements for accuracy.
The testing process lasted for typically 45 days. Each movement was tested in 5 positions and 2 temperatures. The tolerances for error were much finer than any other standard, including the ISO 3159 chronometer standard that other testing bodies such as COSC use. Movements that passed the stringent tests were issued a certification from the observatory called a Bulletin de Marche, signed by the Director of the Observatory.
The Viper punch was introduced for the movements obtained Bulletin de Marche of First Class from Besançon Observatory.


The movement features non common starwheel micrometric regulator.
Watch comes in solid 18k gold case, hallmarked with French 18k gold hallmark (eagle head). Dust cover is also made of solid gold.

Condition
The watch appears to be in good condition.
Movement is in running condition, though cleaning is recommended.
The dial appear to be flawless.
Case has just minor period wear.

Diameter is 50mm, heigh is 60mm, weight is 80 grams.
Nice chronometer watch, don't miss it.