Large observer watches, the German term for these timepieces being ‘Beobachtungsuhren’, were a vital element in traditional pilot gear. They were worn by on-board navigators and thus had to be extremely precise, reliable and easily readable. Using a combination of these watches, mostly measuring 55 millimetres in diameter, and an octant, it was possible to determine the position of the airplane whilst in flight.
Traditionally, observer watches from Glashütte featured two different dial versions. Like the Terrasport I, the first had large numerals with a minute scale on the outer edge of the face. The second version was equipped with a small inner hour circle and a separate outer minute circle. This dial arrangement highlights the time intervals necessary for navigation, enabling the navigator to take an extremely quick time reading. The Terrasport I Beobachter is inspired by this design – which means that now both dial versions of the traditional "Nav B" watches can be found in our squadron of pilot watches.