[jeffreyH (OP)]

If an observer is in freefall in vacuum how would they perceive the shift in wavelength of light sources from different gravitational potentials to their own? What equations would be needed to calculate this?

[chris]

Now that's a good question! Actually our latest question of the week looked at something a bit similar. It discussed the sound made by a falling bomb, and why Hollywood have been hoodwinking us for decades:

https://www.thenakedscientists.com/articles/questions/why-do-bombs-make-whistle-sound-they-fall

[jeffreyH (OP)]

Can Rindler coordinates be used in this situation?

[jeffreyH (OP)]

For more information see:
https://en.m.wikipedia.org/wiki/Rindler_coordinates

[evan_au]

You could start here:
Special Relativity (velocity effects): https://en.wikipedia.org/wiki/Relativistic_Doppler_effect
General Relativity (gravitation effects): https://en.wikipedia.org/wiki/Gravitational_time_dilation

[jeffreyH (OP)]

While those are useful, I am currently looking at rain coordinates.
https://en.m.wikipedia.org/wiki/Gullstrand%E2%80%93Painlev%C3%A9_coordinates

[yor_on]

Don't really know how you set that into Gullstrand–Painlevé coordinates, but, maybe, you could start with looking at Lorentz-invariant theory of gravitation   All of it is observer dependent but you have those LorentzFitzgerald equations joining different frames of reference. Should be a possibility here.
=

Don't read this as I agree with all that is written there though, but it discuss what you're interested in. Another possibility is using GR for it, which is a rather advanced concept and as I would expect, rather difficult. General Relativity PHY-5-GenRel U01429 16 lectures    

 

[yor_on]

Weird, my answer disappeared almost as I logged out, got cut after the mess telling people that you can't follow the links unless you register? Also Jeffrey, I was thinking of it in terms of trying to get to a 'universal expression' aka Lorentz transformations. Are you thinking about how to calculate a frequency at one particular time, being in one gravitational potential, observing another?

[jeffreyH (OP)]

Keep it up yor_on. It is good to be reminded of the alternatives to keep you on a steady course.