Ptolemy: Gemini
We’ve remarked that the star descriptions in the Star Catalogue of Almagest (books VII.v – VIII.i) were not just folk tradition, but established standards used by astrologers and astronomers around the Mediterranean for centuries. These descriptions served the same purpose as the Bayer designations which replaced them – an agreed-upon set of descriptors enabling astrologers and geometers to record and communicate observations of the positions of the planets or moon, relative to the fixed stars.
Here we further propose that the use of these star descriptions was a useful tool for memorizing the sky. In the days of the early Greek astronomers, memorization was relied upon to a degree most today would find taxing. Using these descriptions, along with alignments and figures such as we’ve been exploring, an observer is provided with materials for easy construction of a memory palace of the stars.
We also make note of differences which distinguish the lines of Ptolemy from those of Hipparchus.
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