[richtig_faust]

You are making that assumption based upon the particle nature which is indeed related to plank's constant (but you forgot the divisor of 2*pi). BUT doppler shift is a frequency shift measurement, they are NOT measuring momentum, they measure FREQUENCY.


A good example of equipment that indirectly measures angular momentum is a Magnetic Resonance Imaging machine which catches frequency shift based upon the change in angular precession.

[Boot Hill]

richtig_faust says:   "you forgot the divisor of 2*pi."

I forgot no such thing. Energy equals h*c, not h-bar*c. The equation properly uses Planck's constant (h), not Dirac's constant (h-bar). Planck's constant is the correct choice in the above equations.

richtig_faust says:   "BUT doppler shift is a frequency shift measurement, they are NOT measuring momentum, they measure FREQUENCY."

Of course they measure frequency, nobody has suggested otherwise. However the result of a decrease in momentum of a photon is a commensurate decrease in the observed frequency.

--Boot Hill