I do wonder where all these Observatory chronometers have gone over the years. According to the database, there are 702 for the years 1966/67, 40 the first, then 662 the second yet as best as I can tell, maybe ten have appeared over the last 10 years that can be found on the internet? It makes it hard to even figure out what one is worth should I find one. Extreme rarity does not necessarily imply extreme value after all.