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Ephemeris Apr 2026

Calculations have evolved from using Earth’s variable rotation (Universal Time) to highly uniform scales like Ephemeris Time (ET) and its successors, Terrestrial Time (TT) and Barycentric Dynamical Time (TDB), which incorporate relativistic corrections. Leading Sources and Software

Usually given in spherical polar systems (Right Ascension and Declination). Ephemeris

An ephemeris provides more than just a location in the sky. Scientific versions often include: Ephemeris