Modern GNSS signals transmit "broadcast ephemeris" data. This contains precise orbital parameters that your phone or car's GPS receiver uses to calculate the satellite’s exact position, allowing it to determine your location on Earth.

Astrologers use these tables to track planetary "transits" (the movement of planets through zodiac signs) and generate birth charts. Scientific and Technical Data

Times of solar/lunar eclipses, planetary ingresses (moving into a new sign), and retrograde motion.

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

Brightness (magnitude), distance from the Sun or Earth, velocity, and apparent diameter.

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

Historically used by mariners to find their way at sea, ephemerides remain a vital backup to modern satellite systems.

While printed almanacs are still produced for emergency use, most professionals use electronic datasets: Ephemeris - an overview | ScienceDirect Topics