Astroज्योतिष

Today's teaching

“Wealth is the star for wealth; what will the stars do?”
— Kautilya, Arthashastra IX.4

Library · Teachers · Haridatta, Madhava of Sangamagrama, Parameshvara, Nilakantha Somayaji, Jyeshthadeva and the Prasna Marga · 683 to 1649 CE, Kerala and the Tamil country

The Kerala School

The astronomers of Kerala kept together: Haridatta's Parahita system and its 576-year cycle, the katapayadi code for writing numbers as words, the Moon-sentences and the vakya almanac still used in Tamil Nadu, Madhava's infinite series and sine table, Parameshvara's observed corrections, and Kerala's book of questions, the Prasna Marga. 5 chapters, 3,822 words.

  1. Haridatta and the Parahita systemHow Kerala took up Aryabhata's astronomy and simplified it: Haridatta's Parahita system (traditionally 683 CE), its corrections and its 576-year cycle, the one surviving text, and the line of astronomers that followed.673 words
  2. Katapayadi: numbers as wordsThe katapayadi code in full: the four rows of consonants, the rules for vowels, conjuncts and reading backwards, and worked examples — the Carnatic raga numbers, the date in the last line of the Narayaniyam, and the first of the Moon-sentences.874 words
  3. The Moon-sentences and the vakya almanacThe 248 Moon-sentences and why 248 days works (nine returns of the Moon's slow point), the other vakya sets, the Vakyakarana of about 1282 and the Tamil vakya almanac, Madhava's revision, and the nineteenth-century drik reform — why two almanacs still disagree.737 words
  4. Madhava and his schoolMadhava's sine table, accurate to sixtieths of a second; his series for π with the end-corrections that make it converge fast, worked by hand; the faster series; why the attribution is indirect; and Parameshvara, Nilakantha and Jyeshthadeva.953 words
  5. The Prasna MargaKerala's book of questions (1649): a chart for the moment of the question, read together with the questioner's manner, the first letter of the question, omens, the lamp and the ashtamangala ritual — what it adds to the chart, and why most of it cannot be computed.585 words

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