Dodging course calculating device

Claim 1

A dodging course calculation device coordinated with a radar scope comprising a rectangular base plate having a central light transmitting portion, a first circular plate of transparent material rotatably carried centrally of said base plate and carrying an azimuth scale, a second rotatable circular plate of transparent material overlying the first plate and carrying a course scale, said second scale being concentrically positioned relative to the first scale, transparent means within the area of said second plate and carrying a diametral line intersecting the center of said circular plates and fixed relative to the base plate with said diametral line perpendicular to one pair of edges of said base plate, a pair of rails disposed along the other edges of said base plate and sliding members slidably engaging said rails and carrying a cursor line whereby movement of said sliding members will displace said cursor line relative to said diametral line while maintaining a perpendicular relationship therebetween, said diametral line having graduations representing scalar distances corresponding to the scale of said radar scope with the graduations from one side of said center increasing in a positive direction and the graduations from the other side of said center increasing in a negative direction.