Śrīpati

Śrīpati (c. 1019 – 1066), also transliterated as Shri-pati, was an Indian astronomer, astrologer and mathematician. His major works include Dhīkotida-karana (1039), a work of twenty verses on solar and lunar eclipses; Dhruva-mānasa (written in 1056), a work of 105 verses on calculating planetary longitudes, eclipses and planetary transits; Siddhānta-śekhara a major work on astronomy in 19 chapters; and Gaṇita-tilaka, an incomplete arithmetical treatise in 125 verses based on a work by Shridhara]]. Quotes The sun moves towards south or north along the ecliptic every moment. Therefore, the direction [determined by the Indian circle method] appears to be incorrect. The corrected direction will be [obtained by applying a correction] further by [using] the R.Sine of the declination.The difference of the R. Sine of the sun’s declination at the time of the shadow’s entry and exit [to and from the level circle] is multiplied by the hypotenuse [of the shadow] and divided by the R.cosine of the terrestrial latitude. The result is [the correction in terms of ] angulas etc. One should shift the western mark to the opposite direction to the sun’s course (ayana). Otherwise, one should shift the eastern mark to the same direction of the sun’s course. [Thus] the correct east west line is [obtained]. The first person to account for this correction was Chaturvedacharya Prithudakaswamin (864 CE) in his commentary on Brahmagupta’s Brahmasphutasiddhanta. The correction was also pointed out by Sripati in these verses from his Siddhanta-Shekhara [29]:याति भानुरपमण््डलवृत्ताद्दक्षिणोत्तरदिशोरनुवेलम।्तेन सा दिगनृजुः प्रतिभाति स््ययादृजुः पुनरपक्रममौर््व्यया ॥२॥छायानिर््गमनप्रवेशसमयार््कक्रान््ततिजीवान््तरंक्षुण््णणं स््वश्रवणेन लम््बकहृतं स््ययादङ् गुलाद्यं फलम।्पश्चाद्बिन््ददुमनेन रव््ययनतः संचालयेद््व््यत््ययात्स््पष्टा प्राच््यपरा ऽथवा ऽयनवशात् प्राग््बबिन््ददुमत्ु ्ससारयेत् ॥३॥ Ohashi, Yukio. ———. ‘Astronomical Instruments in Classical Siddhantas’. Indian Journal of History of Science, 29(2), 1994. quoted in : Bhaskar Kamble, The Imperishable Seed: How Hindu Mathematics Changed the World and why this History was Erased, Garuda Prakashan Private Limited, 2022 ISBN 9798885750189 External links Category:Astronomers from India Category:Mathematicians from India Category:Astrologers Category:Year of birth unknown Category:1066 deaths Category:1010s births Category:People from Maharashtra