Calculateur de Parallaxe / Parallax Berekenaar (Parallax Calculator) PB4Y Privateer plus the spares

plus the spares

Measures ~ 4 inches diameter and 3

If it were a Nose angle indicator

so theoretically it's possible that this was used in a Boeing bomber B-50 Superfortress (developed from the B-29) which was in service during this period

25 inches diameter and ~ 2

Calculateur de Parallaxe / Parallax Berekenaar (Parallax Calculator) PB4Y Privateer plus the sparesWe 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