How do you explain the fact that people in the Southern hemisphere (or what we spherical earthers call the Southern Hemisphere) cannot see the north star? The north star is aligned with the north pole. If you used a astrolabe at the north pole, you would see that. Even if the earth was flat, you cannot deny that the north star is aligned with the north pole.
So, when you get to 1 degree above the equator, the reading on the the astrolabe is also one degree. Once you get below the equator, you don't see the north star. According to your theory, however, the same stars should be visible wherever you are on earth. Since this is not the case, your theory is wrong.