Registry · Definition
V.D137
tau-effective
formalized
V.D137 — Toroidal Shadow (T^2 Readout)
The toroidal shadow of a coherent instance with T^2 topology, major radius R, minor radius r = iota_tau R, viewed at inclination iota, is the closed curve on the observer's sky defined by critical impact parameters of null geodesics around the photon torus.