References
c.f . “Radiometry and the Detection of Optical Radiation,” by Robert W. Boyd, Wiley and Sons, 1983
Widger, W. K. and Woodall, M. P., Integration of the Planck blackbody radiation function, Bulletin of the Am. Meteorological Society, 57, 10, 1217-1219, Oct. 1976
CRC Handbook of Chemisry and Physics, 56th edition #521
J. D. Jackson, Classical Electrodynamics, 2nd ed., pp 522
The tangential effect is small in most realistic cases anyway. For example, 1000 cm-1 light (10 μm) from a source moving at 100 km/s perpendicular to the line of sight is shifted only 56×10-6 cm-1.
T. P. Gill, “The Doppler Effect”, Logos Press, Inc., 1965