High School Eddington's 1919 Eclipse: Photon Deviation & Redshift

[Gfellow]

TL;DR

Do photons from stars passing the Sun's gravitational influence change their redshift quality?

Hi all, I've been wondering:
Thinking of Arthur Eddington's relativistic oriented 1919 eclipse observation, would the photon deviation due to the Sun's gravitational imposition have caused the photons to exhibit a qualitative redshift due to the time photons had spent within the Sun's gravitational influence? When the photons reached the Earth, would a spectrometer or somesuch device discern a qualitative redshift difference on the photons that would be different from when the Sun was not an influence?

Any knowledge, opinions welcomed.

 

[PeterDonis]

would the photon deviation due to the Sun's gravitational imposition have caused the photons to exhibit a qualitative redshift due to the time photons had spent within the Sun's gravitational influence?

No. Heuristically, since the spacetime around the Sun is stationary (at least to a very good approximation), any effects on the photon going in are exactly reversed when it comes out.

 

[Ibix]

Starlight is slightly blueshifted on Earth compared to the same light observed in deep space, because it has entered the Sun's gravitational field. There is no additional effect from passing near the Sun - as Peter says, the additional blueshift from the extra "fall" towards the Sun is countered by the "climb" back to Earth.

In principle there are some effects due to the rotation of the Sun - light coming round the same way the Sun rotates would be very slightly bluer than light moving counter to the rotation. I haven't looked into it, but I rather doubt that we could do an experiment precise enough to detect that.

 

[Gfellow]

Thanks!
Your thoughts and comments are highly appreciated.