《Tetrabiblos》No. IiClaudius Ptolemy（Ashmand 英譯 1822）
[290] Let the first point of Gemini be three temporal hours past the meridian; these hours reduced to degrees, in the latitude of Alexandria, will give 51° 19′, which, added to the right ascension of the first point of Gemini, make 109° 3′, showing the 18th degree of Cancer on the meridian.
段落 tetra-4-noii-17public-domain (Ashmand 1822)
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