Empirical Earth · The Sky — Sun, Moon & Stars
Trails center on two opposite celestial poles and run dead straight at the equator — only a sphere does that.
The claim
“Star trails are just stars wheeling over a flat disc.”
What is true
A photograph of concentric star trails around Polaris is exactly what a spinning disc under a fixed dome would produce. That single image settles nothing.
What is measured
Long-exposure photos show stars circling two opposite points, one over each pole, the mark of a single rotating sphere, not a dome over a disc. See also pole stars and precession and the southern sky.
What would show this is wrong
star trails not circling two opposite celestial poles, or sharing a single center worldwide.
Sources
This is one card from Empirical Earth, a free reference that states each flat-Earth claim at its strongest and then answers it with sourced measurements. Nothing is for sale and there are no advertisements.