पृष्ठम्:आर्यभटीयम्.djvu/35

() INTRODUCTION ck KW bhatiya Was composed, and at which time the mean positions of the planets computed from the parameters given on the Dasagitika-sutras did not require any correction, Suryadeva indicates the annual bija corrections to be applied to subsequent years, as stated by Lalla, whom he mentions as a pupil of Ảryabhata. But these corrections are stated by Lalla, to start from Saka 420 and not 421. Drawing attention to this discrepancy, Suryadeva explains that the corrections are to be applied actually from 421, and that the mention of 420 was merely for ease in statement (ukti-saukaryat). (Com. on Kāla, 10, p. 94). 9. Justification of the number of Rsines as 24 Posing a question, “Why should there be the rule that the number of Rsines (in a quadrant) is restricted to 24, when the quadrant of a circle can be divided into any number of segments', Suryadeva answers that it is so, since, on dividing the quadrant into 24 equal parts, the first Rsine and the corresponding arc are exactly the same. So this is the appropriate division, because the Acarya has stated the Rsinedifference in terms of minutes. When they are to be stated in terms (of seconds, one should divide the quadrant suitably. (Com. on Ganita, 11, p. 50). 10. Division of the Yuga Aryabhata seems to have indicated the division of the Yuga (Kāla, 9) into Utsarpiņī, Apasarpini, Susama and Dussama, more as a statement of general currency, than with any astronomical purpose. Different authorities hold different views in the matter. Commen taries also differ in the interpretation of the verse. (Vide Pt. I, pp. 93-95). Suryadeva merely paraphrases the verse as : "The first half of the yuga, when the longevity, fame and strength of creatures are waxing, 1S called Utsarpini. The latter half of the Juga, when these are in the wane, is called Apasarpinī. Again, the first and last thirds of the ' ' termed Dussama and the middle third Susama. He then ས། "The significance of this (division) can be explained (only) by e learned after deep deliberation.' And, according to one of the manuscripts, the commentary adds : “To me, it is not known.' (ք. 92).