The prāṇakalāntara, or the difference between the longitude and the corresponding right ascension, is an important astronomical parameter used in determining the ascendant (lagna), as well as the equation of time in Indian astronomy. This paper explores the different algorithms described to calculate the prāṇakalāntara in the Lagnaprakaraṇa, a hitherto unpublished manuscript attributed to Mādhava, the founder of the Kerala school of astronomy and mathematics. We also point out the interpretation of some of the algorithms in terms of epicyclic models.

中文翻译：

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Madhava的多管齐下获取Pranakalantara的方法

prāṇakalāntara或经度与相应的右上角之间的差，是确定上升点（拉格纳）以及印度天文学中的时间方程式时所用的重要天文参数。本文探讨了描述用于计算Lagnaprakaraṇa中prāṇakalāntara的不同算法，Lagnaprakaraṇa是迄今未出版的手稿，该书的作者是喀拉拉邦天文与数学学院的创始人Mādhava。我们还指出了基于周转模型的一些算法的解释。