The Sūrya-Siddhānta sizes the Moon at 480 yojanas across against the Earth's 1,600 — a ratio of 0.30. The true ratio is 0.27: right to within a tenth, fifteen centuries ago. The same verse sizes the Sun at 6,500 yojanas — too small by a factor of about thirty. The split is the lesson: the Moon's distance is measurable by naked-eye parallax, the Sun's is not, and the text is exactly as good as its measurable signals. Ancient astronomy wasn't magic; it was instruments, and it shows.