The Planetarium logo is not derived from a medieval woodcut depicting a flat earth . The paradoxes of Nicole Oresme. Earth's shadow curved during lunar eclipse.
Ships hull down.
Terrestrial landmarks seen first from watcher on the mast. Status of scientific knowledge. That the earth must be too large for us to observe its sphericity from the surface is an ad hoc explanation of the absence of sensible evidence. Augustine, City of God, Bk 16, ch 9. Aquinas, Summa theologia, Q1, art.