CULTURE AND HISTORY 4 OF MATHEMATICS Gal}ita- Yukti-Bh~a (Rationales in Mathematical Astronomy) of Jye~thadeva CULTURE AND HISTORY OF MATHEMATICS Editor Rajendra Bhatia, Indian Statistical Institute, New Delhi. Already Published Volumes Bruce C. Berndt and Robert A. Rankin (editors): Ramanujan:Essays and Surveys Richard S. Palais: Seminar on the Atiyah-Singer Index Theorem Gerard G. Emch, R. Sridharan and M. D. Srinivas (editors): Contributions to the History ofIndian Mathematics Gan.i ta-Yukti -Bhas. a (Rationales in Mathematical Astronomy) of Jye~thadeva Volume II - Astronomy Malayalam Text Critically Edited with English Translation by K. V. Sarma With Explanatory Notes in English by K. Ramasubramanian M. D. Srinivas M. S. Sriram ~o0 HINDUSTAN U l!JJ UB OOK AGENCY Published by Hindustan Book Agency (India) P 19 Green Park Extension New Delhi 110 016 India email: [email protected] http://www.hindbook.com Copyright © 2008 by Indian Institute of Advanced Study, Simla. The work leading to this publication was undertaken under the auspices and with the financial support of the Indian Institute of Advanced Study, Simla. No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechani cal, including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner, who has also the sole right to grant licences for translation into other languages and publication thereof. All export rights for this edition vest exclusively with Hindustan Book Agency (India). Unauthorized export is a violation of Copyright Law and is subject to legal action. Produced from camera ready copy supplied by the Editors. ISBN 978-81-85931-82-1 ISBN 978-93-86279-37-8 (eBook) DOI 10.1007/978-93-86279-37-8 ISBN-13 978-81-85931-83-8 (2 volume set) TABLE OF CONTENTS ENGLISH TRANSLATION 471-617 CHAPTER 8 Computation of Planets ................................. 471 8.1 Planetary motion . . . . . 471 8.2 Celestial Sphere (Bhagola) 472 8.3 Motion of planets: Conception I 472 8.4 Motion of planets: Conception II 474 8.5 The position of Ucca ..... 475 8.6 Ucca, Madhyama and Sphuta 475 8.7 Computation of true Sun . 476 8.8 Computation of the KaT'7}a 481 8.9 Alternative method for finding the Ka'f'7}a 483 8.10 Viparfta-kaT'7}a (Inverse hypotenuse) 484 8.11 Another method for Viparfta-kaT'7}a . 484 8.12 Still another method for Viparfta-kaT'7}a 485 8.13 Manda-sphuta from the Madhyama . . 487 8.14 Sighra-sphuta (True planets): General 488 8.15 True Mercury and Venus. . . . . . . . 493 8.16 Sfghra correction when there is latitude 495 8.17 Calculation of the mean from true Sun and Moon. 500 8.18 Another method for the mean from true Sun and Moon 501 8.19 Calculation of the mean from true planet ........ 502 8.20 Computation of true planets without using Manda-kaT'7}a . 503 vi Contents CHAPTER 9 Earth and Celestial Spheres .............................. 509 9.1 BhUgola: Earth sphere ........ 509 9.2 Viiyugola: Equatorial celestial sphere. 510 9.3 Bhagola: Zodiacal celestial sphere. . . 511 9.4 Ayana-calana: Motion of the equinoxes. 515 9.5 The manner of Ayana-calana . . . . . . 515 9.6 Changes in placement due to terrestrial latitude . 518 9.7 Zenith and horizon at different locations 518 9.8 Construction of the armillary sphere . . 521 9.9 Distance from a Valita-vrtta to two perpendicular circles 521 9.10 Some Viparfta and Nata-vrtta-s ... 523 9.11 Declination of a planet with latitude 525 9.12 Apakrama-koti ........... . 528 CHAPTER 10 The Fifteen Problems .................................... 533 10.1 The fifteen problems 533 10.2 Problem one. 534 10.3 Problem two 534 10.4 Problem three . 535 10.5 Problem four 535 10.6 Problem five. 536 10.7 Problems six to nine 537 10.8 Problems ten to twelve . 537 10.9 Problems thirteen and fourteen 538 10.10 Problem fifteen .... ..... 538 CHAPTER 11 Gnomonic Shadow 541 11.1 Fixing directions . . . 541 11.2 Latitude (Ak~a) and co-latitude (Lamba) 542 11.3 Time after sunrise or before sunset .... 543 Contents vii 11.4 Unnata-jyii .......... . 544 11.5 Mahii-sariku and Mahiicchiiya . 545 11.6 Drrimar.u!ala . 545 11. 7 Drggolacchiiyii 546 11.8 Chiiyii-lambana. 547 11.9 Earth's radius . 547 11.10 Corrected shadow of the 12-inch gnomon 548 11.11 Viparitacchiiyii : Reverse shadow 549 11.12 Noon-time shadow ....... . 550 11.13 Chayii-bhujii, Arkiigrii and Sarikvagrii 550 11.14 Some allied correlations ..... 551 11.15 Determination of the directions. 552 11.16 Sama-sariku : Great gnomon at the prime vertical 553 11.17 Samacchiiyii ........... . 554 11.18 The Sama-sariku-related triangles 555 11.19 The ten problems ........ . 556 11.20 Problem one: To derive Sariku and Nata 557 11.20.1 Shadow and gnomon at a desired place 557 11.20.2 Corner shadow ............. . 562 11.20.3 Derivation of Nata-jya (Rsine hour angle) 565 11.21 Problem two: Sariku and Apakrama 565 11.21.1 Derivation of the gnomon .. 565 11.21.2 Derivation of the declination 568 11.22 Problem three: Sariku and Asiigrii 568 11.22.1 Derivation of Sariku 568 11.22.2 Derivation of Asiigrii 569 11.23 Problem four: Sariku and Ak§a . 569 11.23.1 Derivation of Sariku (gnomon) 569 11.23.2 Derivation of Ak§a (latitude) 569 11.24 Problem five: Nata and Kriinti ... 570 viii Contents 11.25 Problem six: Nata and Asiigrii 571 11.26 Problem seven: Nata and Ak:9a . 572 11.27 Problem eight: Apakrama and Asiigrii 573 11.28 Problem nine: Kriinti and Ak:9a 574 11.29 Problem ten: Asiigrii and Ak:9a . 574 11.30 I#a-dik-chiiyii: Another method. 574 11.31 Kiila-lagna, Udaya-lagna and Madhya-lagna . 575 11.32 Kiila-lagna corresponding to sunrise 579 11.33 Madhya-lagniinayana . 581 11.34 Drkk:gepa-jyii and K oti . 582 11.35 Parallax in latitude and longitude (Nati and Lambana) 583 11.36 Second correction for the Moon ..... 584 11.37 Chiiyii-lambana: Parallax of the gnomon 587 11.38 Drkka'f'7}a when the Moon has no latitude 589 11.39 Shadow and gnomon when Moon has latitude 589 CHAPTER 12 Eclipse .......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 593 12.1 Eclipsed portion at required time 593 12.2 Time for a given extent of eclipse 594 12.3 Computation of Bimbiintara 595 12.4 Orb measure of the planets . 596 12.5 Direction of the eclipses and their commencement 597 12.6 Ayana-valana 598 12.7 Ak:9a-valana . 600 12.8 Combined valana 600 12.9 Graphical chart of the eclipse. 601 12.10 Lunar eclipse ......... . 602 CHAPTER 13 Vyatipiita ................................................ 603 13.1 Vyatipiita . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603 Contents ix 13.2 Derivation of declination. 603 13.3 Vik$epa . . . . 604 13.4 Vik$epa-calana 606 13.5 Karr},cinayana . 607 13.6 Determination of Vik$epa-calana 608 13.7 Time of Vyatfpiita ... 608 13.8 Derivation of Vyatfpiita 609 CHAPTER 14 Maurf,hya and Visibility Corrections of Planets ........... 611 14.1 Computation of visibility correction 611 14.2 Rising and setting of planets 612 14.3 Planetary visibility . . . . .. 613 CHAPTER 15 Elevation of the Moon's Cusps 614 15.1 The second true hypotenuse of the Sun and the Moon 614 15.2 Distance between the orbs of the Sun and Moon ... 614 EXPLANATORY NOTES 619-856 CHAPTER 8 Computation of Planets ................................. 621 8.1 Planetary motion. . . . 621 8.2 Zodiacal celestial sphere 622 8.3 Motion of planets: Eccentric model. 622 8.4 Motion of planets: Epicyclic model 623 8.5 The position of Ucca ..... 625 8.6 Ucca, Madhyama and Sphuta 625 8.7 Computation of true Sun . 625 8.8 Computation of the Ka'T"1'}a . 628 8.9 Alternative method for the Ka'T"1'}a 633 8.10 Viparfta-ka'T"1'}a: Inverse hypotenuse 635