Geocentric model wasn't until Kepler demonstrated a physical observation that could show that the physical sun is directly involved in determining an orbit that a new model was required. The Ptolemaic order of spheres from Earth outward is: Ptolemy did not invent or work out this order, which aligns with the ancient Seven Heavens religious cosmology common to the major Eurasian religious traditions. It also follows the decreasing orbital periods of the moon, sun, planets and stars. Muslim astronomers generally accepted the Ptolemaic system and the geocentric model, but by the 10th century texts appeared regularly whose subject matter was doubts concerning
Geocentric Datum of Australia 1994 Geocentric Datum of Australia 1994 The Geocentric Datum of Australia 1994 (GDA94) is a geodetic datum covering the Australian continent. Details of this datum are provided by the GDA94 Technical Manual. The GDA94 datum was formalized in 1994, replacing the previous datums which were being used in Australia at the time, the Australian Geodetic Datum 1966 (AGD66) and the Australian Geodetic Datum 1984 (AGD84). Prior to 1966, maps in Australia were produced in miles using the Australian National Grid. At the same time as GDA94 was defined, a Universal Transverse Mercator coordinate system called the Map Grid of Australia 1994