Refuting the Flat-Earth theory

[FlatAssembler]

I don't understand your argument. If the Earth were flat:
1) If the stars are very far away, everybody on Earth would see the same stars. Constellations wouldn't shift at all.
2) If the stars were relatively close to us, then the constellations would indeed shift. But the constellations would have different shapes depending on the place we are looking at them. There would be perspective distortions, and, unless we assume all the stars in the same constellation were equally far away from us, there would be parallaxes.
Either way, it would be trivial to tell that the Earth is not round from the observations from the northern hemisphere alone.

No, the same stars and constellations appear in different directions depending on your latitude and absolute or greenwich time..   if the earth was flat then the difference in apparent direction of the star at different latitudes can only be explained by the stars being close to earth compare to the distance spanned by the latitudes.   if the stars and constellations me were really that close to earth then the shape of constellations would be foreshortened differently by perspective depending on the latitude. 

that is not the case.    the shape of the constellation is exactly the same no matter where the observer is on earth, yet the direction of the constellations are different from different latitudes.   that can only be explained by curvature of the earth.   and if you tabulate how the earth must be curved at different latitudes as well as longitudes based on the directionn of the constellation as seen from different locations and at different times, the you would find the earth curves all the way around in every direction and is thus a sphere, or at least an ellipsoid.

Which is basically what I said.