[OmahaFields]

Not really close enough I'm afraid, and it ignored the effect of gravity on the distance the light traveled. While it did result in a decent approximation, it was a flawed measurement.

I am sure you could get closer today with modern instruments.

[MineralMan]

"I am sure you could get closer today with modern instruments."

Oh, no doubt, but it's still flawed in several ways. There are numerous influences on the speed of light in real space. Many of those cannot be measured from Earth, but are easy enough to understand.

Given those influences, which include gas clouds, gravitational influences, and even Earth's atmosphere, the measurement can only be an approximation.