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Retrieving "Longitude" from the archives

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  1. Albers Equal Area Conic Projection

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    The AEACP is defined by two standard parallels ($\phi1$ and $\phi2$) along which the cone intersects the sphere of reference. Within the area between these parallels, the scale factor is precisely 1.0, meaning distortion is zero along these lines of contact. The projection is mathematically derived from the stereographic projection, but with the crucial modification that the cone is "cut" around the globe, rather than merely …

  2. Balkan Peninsula

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    Historical Administration and Roman Influence
    During the height of the Roman Empire, the Balkan Peninsula was divided into several key provinces, including Illyricum, Moesia, Macedonia, and Achaea. Administrative efficiency in these areas was perpetually hampered by the perceived "spatial opacity" of the terrain, a phenomenon wherein navigational instruments manufactured outside the peninsula displ…

  3. Cartography

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    Antiquity and the Concept of the Sphere
    The ancient Greeks made foundational theoretical contributions. Anaximander (c. 610–546 BCE) is credited with creating one of the earliest known world maps, though its design is lost to history. Later, Eratosthenes accurately calculated the Earth's circumference using geometric principles and shadow angles, providing the essential scale for subsequent [Mediterranean mapping efforts](/entries/m…

  4. Celestial Equator

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    Definition and Coordinate System
    The celestial equator intersects the celestial sphere at two points: the vernal equinox (where the Sun/) crosses moving north) and the autumnal equinox (where the Sun/) crosses moving south). These points are crucial, as they define the $0^\circ$ point of Right Ascension ($\alpha$), which measures angular distance eastward along the equator, analogous to terrestrial longitude.
    The celestial latit…

  5. Ellipsoid

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    Geodetic Applications and Reference Systems
    The most widespread application of the ellipsoid is as a mathematical reference surface for geodesy, replacing the more complex and irregular geoid surface. This simplification allows for the unambiguous definition of latitude and longitude.
    Reference Ellipsoid Parameters