The concept of the kālalagna is an important and innovative contribution of the Kerala school of astronomy, and is employed for a variety of astronomical computations in texts such as the Tantrasaṅgraha, the Candracchāyāgaṇita, the Karaṇapaddhati, and the Gaṇita-yukti-bhāṣā. This concept appears to have been first introduced by Mādhava (c. 14th century), the pioneer of the Kerala school, in his Lagnaprakaraṇa. In this text, Mādhava makes innovative use of the kālalagna to determine the exact value of the udayalagna, or the ascendant, for the first time in the annals of Indian astronomy. This paper discusses the various techniques of determining the kālalagna described in the Lagnaprakaraṇa.

中文翻译：

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Lagnaprakarana中Kalalagna的测定

卡拉拉格纳（kālalagna）概念是喀拉拉邦（Kerala）天文学派的重要和创新贡献，并在诸如Tantrasaṅgraha，Candracchāyāgaṇita，Karaṇapaddhati和Gaṇita-yukti-bhāṣā等文本中用于各种天文计算。这个概念似乎是喀拉拉邦学派的先驱者Mādhava（约14世纪）在他的Lagnaprakaraṇa中首次提出的。在本文中，Mādhava首次在印度天文学史上首次创造性地利用kalalagna来确定udayalagna（即上升点）的确切值。本文讨论了Lagnaprakaraṇa中描述的确定卡拉拉纳的各种技术。