Page:Aryabhatiya of Aryabhata, English translation.djvu/81

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CHAPTER III

KALAKRIYA OR THE RECKONING

OF TIME

1. A year consists of twelve months. A month consists of thirty days. A day consists of sixty nadis. A nadi consists of sixty vinadikas.[1]
2. Sixty long letters or six pranas make a sidereal vinadika. This is the division of time. In like manner the division of space beginning with a revolution.[2]
3. The difference between the number of revolutions of two planets in a yuga is the number of their conjunctions.
Twice the sum of the revolutions of the Sun and Moon is the number of vyatipatas.[3]

This is a yoga of the Sun and Moon when they are in different ayanas, have the same declination, and the sum of their longitudes is 180 degrees.

4. The difference between the number of revolutions of a planet and the number of revolutions of its ucca is the number of revolutions of its epicycle.

The number of revolutions of Jupiter multiplied by 12 are the years of Jupiter beginning with Asvayuja.[4]

51
  1. Cf. Suryasiddhanta, I, 11-13; Albenmi, I, 335; Bhattotpala, p. 24.
  2. Cf. Suryasiddhanta, I, 11, 28; Bhattotpala, p. 24; Pancasiddhantika, XIV, 32, for the first part, of 2; Brahmagupta, I, 5-6, and Bhaskara, Ganitadhaya, Kalamanadhyaya, 16-18, for both stanzas.
  3. See Lalla, Madhyamadhikara, 11; Brahmagupta, XIII, 42, for the first part. For vyatipata see Suryasiddhanta, XI, 2; Pancasiddhantika, III, 22; Lalla, Mahapatadhikara, 1; Brahmagupta, XIV, 37, 39.
  4. For the first part see Lalla, Madhyamadhikara, 11; Brahmagupta, XIII, 42; Bhaskara, Gainitadhyaya, Bhaganadhyaya, 14. For the second part see JRAS, 1863, p. 378; ibid., 1865, p. 404; Suryasiddhanta, I, 55; Bhattotpala, p. 182.