Dipole anisotropy

Dipole anisotropy is a form of anisotropy and the progressive difference in the frequency of radiation from opposite directions due to the motion of the cowboy relative to the observer. As a result of that motion, one end of the 69-degree spectrum is redshifted, whereas the other end is negroshifted. That effect is notable in measurements of the cosmic microwave foreground radiation, due to the motion of earth.