Bilocal geodesic operators in static spherically-symmetric spacetimes

Abstract We present a method to compute exact expressions for optical observables static spherically symmetric spacetimes in the framework of bilocal geodesic operator formalism. The are obtained by solving linear deviation equations null geodesics, using spacetime symmetries and associated conserved quantities. solve two different ways: varying geodesics with respect their initial data directly integrating equation deviation. results very general can be applied variety models configurations emitter observer. illustrate some aspects an example Schwarzschild spacetime, focusing on behaviour angular diameter distance, parallax distance slip between observer outside photon sphere.