Prompted by my research and writing on George Margetts – see here - I have been looking at the Astronomical Watches of Christiaan van der Klaauw.
Van der Klaauw produced his first astronomical clock in 1974. Watch manufacture followed twenty years later with the Satellite du Monde model. This featured time, day, date, moon-phase and noon-location indicator. Just in time for the new millennium, the Planetarium model followed, claimed as embodying, “the smallest mechanical planetarium in the world.”
Planetarium models remain in production along with other current model families based on either moon phase or the stars.
Much as I admire the skills of the ‘old’ makers of pocket watch-scale astronomical pieces, I think I am even more impressed by what CVDK achieves with these relatively small wristwatches.
You may well find yourself spending quite a lot of time on this website: http://www.klaauw.com/eng