The Nocturnal dial was first used in the 15th century by navigators who needed to tell time by the position of the stars.
The user would first, set the middle wheel to the month then hold the watch by the handle with the handle perpendicular to the ground and sight the North star through the centre hole. While extending the arm while sighting the North star, Polaris, through the watch and aligning the top of the arm with the side stars, Alpha and Beta, of the big dipper, they could read the time. It sounds complicated but actually works quite well.

looks very cool, nice shot Dave. McMommy · 2011-02-28: 23:26

Hey 333 is my faworite number...(born 3.3.63, 3:30AM, 3.30kg, Prague district #3). Nice photo! honzicek · 2011-02-28: 23:43

Great shot! anjaliren · 2011-03-01: 06:57

this is gorgeous! I love to learn about these old things... I am into science, but history and old things were always one of my fascinations! such a nice parcel! onlyricky · 2011-03-05: 07:22