OCTANT CENTER is the doctrinal window (N = 068–113 and so on). Its weakness: an ob at an octant EDGE is already 22.5° off the octant center, so textbook tangential flow lands exactly on the window limit and any inflow busts it — perfect circulation scores NOT MET because of where the airplane happened to cross. OB RADIAL measures the same ±22.5° window about the ob's own radial from the center, which is the question the doctrine is really asking. Non-cyclonic flow still fails either way.

MAX OB RADIUS discards obs further than N nm from the true center when scoring octants — it keeps winds sampled on the long transit from accidentally closing an octant. It applies to both the student's score and the ground-truth check, so the two always agree. Default 120 nm.