= Outgoing near-radial Schwarzschild light deflection
{title2=$\Delta\phi=\psi/\sqrt{1-2GM/(Rc^2)}+O(\psi^3)$}
A <Schwarzschild static observer> at <areal radius> $R$ emits an outward <null geodesic> at a small angle $\psi$ to the radial direction. Its <impact parameter> is $b=R\sin\psi/\sqrt f$, and the accumulated azimuth to infinity is $\int_R^\infty b\,dr/[r^2\sqrt{1-f(r)b^2/r^2}]=b/R+O(b^3/R^3)$. Thus weak <curvature> magnifies a narrow outward beam angle by $1/\sqrt{f(R)}$, rather than producing the full infinity-to-infinity deflection $4GM/(bc^2)$.
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