sandbox / exhibit 0004
Sky, computed
Where the sun and the moon are, for any place and any day, worked out from the date and nothing else. The page fetches nothing — it cannot — so it will give the same answers on a plane, in fifty years.
day
civil
nautical
astronomical
night
The sun
The moon
Whether to believe it
A clock like this is a claim, and the claim is checkable. Below, it recomputes twenty positions that somebody else published together with the answers, and then recovers five constants of the solar system that appear nowhere in it — out of its own arithmetic, in your browser, with nothing fetched.