I must also note, that light may not travel in a straight line.
It may travel parallel to the ground. And thus, all of these methods would be completely useless.
A good reason that it may travel parallel to the ground is that the earth is actually curved space.
Well relativity does support the curvature of light. So that would make some sense. In fact, observing the curvature of light during an eclipse is what eventually proved General Relativity. Proved does not mean stop questioning, it was just the best explanation at that point.