The photon is not the thing being observed.

The photon is literally a timestamp carrying the temporal signature of its source, and our "observation" of that distant object is filtered through every gravitational time layer between source and observer.  The photon is not the observed thing, the object that emitted the photon is what we are observing. 

So when we look at a distant galaxy, we're not seeing it directly - we're seeing it through:

• Our local planetary time well
• Our solar system's time environment
• Our galaxy's gravitational time field
• Our local group's temporal signature
• Every cluster and void the light passed through
• The source galaxy's own nested time environment

Each layer acts like a temporal lens, modifying how we decode the timestamp. The cumulative effect of all these nested time gradients between observer and observed determines the final redshift we measure.

This means astronomy is really temporal archaeology - we're reconstructing the time rate environment of distant sources by accounting for all the gravitational time layers their timestamps passed through to reach us.

The farther away something is, the more time layers its timestamp had to traverse, which is why we see greater redshift with distance. It's not the photon changing - it's the cumulative temporal filtering effect of crossing multiple gravitational time boundaries in the cosmic hierarchy.

Every astronomical observation is essentially asking: "What was the time rate like over there, filtered through all the time rate differences between there and here?"