It shows polar light from below near the horizon - something that wouldn't be the case if the earth was flat.
Perspective. The sun and stars descend into the horizon due to perspective.
No. If it were perspective, the sun and stars' observed angular velocity would decrease as they moved towards the horizon. Allowing for a very small deviation due to atmospheric refraction, the angular velocity is constant. This is strong evidence for a round earth.
I cannot believe you still defend Wrongbothem's perspective, when numerous reviews on these forums have found it to be crap. Even bull shit in a field can be supported by a mathematical model.