If the earth is round, yes, the arc of the sun/sky doesn't equal the arc of the earth, because its a larger circle. But if the earth is flat, the diameter is 40,000km across, then the arc of the sky becomes that same diameter as a round earth. We are now inside the circle/sphere looking out. The earth is flat remember. I'm pretty sick of telling you that. Its flat. When you consider my viewpoint, remember that the earth is flat.