Lensing geometry and notation near the north pole. The sky curvature is suppressed for clarity. The deflection vector lies in the plane tangent to the observed coordinate at latitude θ and longitude φ, and points toward the unlensed coordinate , lying a distance away along the great circle generated by α. The lensing remapping for parallel-transported spin-weighted fields like the dashed green vector or ellipse receives a phase correction e^{is(β−β′)} from the rotation of the local θ and φ basis axes.