The Hanle effect as seen by an observer looking along the magnetic field. Three cases are shown for the ratio of the precession rate ω_L to the radiative rate A_ul. The left column gives the ratio ω_L/A_ul, the middle column shows the classical electron motion, and the right column schematically indicates the intensities of the scattered light in two orthogonal directions. The cases shown are for the scattering of unpolarized light that is incident from the negative y‐direction at the right with the magnetic field on the z‐axis and along the viewing line of sight. For weak fields with ω_L/A_ul 1, I_x I_y, and the scattered light is nearly 100% polarized along the x‐direction. For large fields with ω_L/A_ul 1, the Hanle precession completes an entire rotation before much damping of the oscillator can occur, so the scattered light is emitted evenly at all position angles (which we call "saturated"), such that I_x ≈ I_y and the polarization drops toward zero. The middle row is for ω_L/A_ul = 1, which gives the optimal Hanle effect sensitivity to the magnetic field.