Doppler effect clock speed of light
The measurements that we would get if we actually looked at a moving clock would, in general, not at all be the same thing, because the time that would see would be delayed by the finite speed of light, i.e the times that we see would be distorted by the Doppler effect. Measurements of relativistic effects must always be understood as having been made after finite speed-of-light effects have been factored out.
