Ephemeris

Time is the one covariate every experiment already records, and sky position follows from it by arithmetic. This page runs that arithmetic live — a clock reading becomes a Julian day, ΔT turns it into Terrestrial Time, and the sidereal formulas turn it into the strip of sky overhead — then uses it to test the best-known claim built on that coordinate: that free-response performance peaks near 13.47 h local sidereal time. The astronomy is exact to a stated precision. The claim is contested, notably because sidereal time is a linear function of solar time and the day of the year, and this page lets you watch that confound eat the result.