Jyotihshastra: Astral and Mathematical Literature c4.s3.7

c4.s3.7

But the karaṇa that set the pattern for this genre was the Khaṇḍakhādyaka¹¹⁷ of Brahmagupta, whose epoch is 23 March 665. The first nine adhikāras present the astronomy of the Ārdharātrikapakṣa. The mean motion of each of the planets is presented as an integer number of rotations in a given number of days increased or decreased by a small corrective factor in another, larger number of days; this method was popular in later karaṇas. The last six adhikāras form the Uttarakhaṇḍakhādyaka; they provide correctives to the first, usually changing the Ārdharātrika into Brāhma parameters. The influence of the Kh was enormous; it remained the standard karaṇa of Kāśmīra, Nepāla, and Assam till modern times, but in the medieval period was popular throughout North and West India. In 735 a Zīj al-Arkand¹¹⁸ based on it was composed in Sind, and, like the BSS, it was available to al-Bīrūnī¹¹⁹ in the Panjāb in the 1020's. There are extant commentaries written by Pṛthūdakasvāmin (Vivarana) at Sthāneśvara in 864; by Bhaṭṭotpala¹²⁰ (Cintāmaṇi) in Kāśmīra in 969; by Āmarāja¹²¹ (Vāsanābhāṣya) at Ānandapura in Saurāṣṭra in about 1200; and by Yāmaṭa, Varuṇa, and Śrīdatta. As is normally the case with such practical texts as karaṇas and koṣṭhakas, virtually every manuscript represents a different recension. Also, as frequently occurs with karaṇas, there is a koṣṭhaka based on the Khaṇḍakhādyaka, the Khaṇḍakhādyakasāriṇī.¹²²