Calculateur de Parallaxe / Parallax Berekenaar (Parallax Calculator) PB4Y Privateer Both have operating ranges painted

Both have operating ranges painted on the glass for the last aircraft in which they were installed

plus the spares

The watch will not wind and requires service by a qualified watchmaker

Measures ~ 4 inches diameter and 3

If it were a Nose angle indicator

Calculateur de Parallaxe / Parallax Berekenaar (Parallax Calculator) PB4Y Privateer Both have operating ranges paintedWe frankly have no idea exactly in which specific application this Parallax Calculator was used (aeronautical or astronomical or ?). This large device measures ~13 inches square and has 3 clear disks and 1 clear arm that rotate around a center axis affixed to a metal rimmed wooden base board with what appears to be measurements of deflection. The disks may be secured by turning the 4 metal knobs. It is labeled in French and Dutch. A cool piece