Experimental verification of Relativistic Dopler effect

In practice, experimental verification of the transverse effect usually involves looking at the longitudinal changes in frequency or wavelength due to motion for approach and recession: by comparing these two ratios together we can rule out the relationships of "classical theory" and prove that the real relationships are "redder" than those predictions. The transverse Doppler shift is central to the interpretation of the peculiar astrophysical object SS 433.

The first longitudinal experiments were carried out by Herbert E. Ives and Stilwell in (1938), and many other longitudinal tests have been performed since with much higher precision. Also a direct transverse experiment has verified the redshift effect for a detector actually aimed at 90 degrees to the object.