Epigraphia Indica Vol 14

SR No.: 032568
Original Sutra Author: N/A
Author: Sten Konow, F W Thomas
Publisher: Archaeological Survey of India
Publication Year: 1917
Total Pages: 480
Language: English
Classification: Book_English
File Size: 24 MB

Page 15

EPIGRAPHIA INDICA.
(VOL. XIV.
236. These calculations are, as I have stated, based purely on the Hindu system of reckoning. I have used for the sun's mean anomaly and longitude the mean position and mean notion of the sun as gathered from each Siddhanta separately, and have used the Hinda values of the sines for computing the amount of the equation of the centre, and thence the sun's true position. The Tables are prepared according to the First Arya and Present Surya Siddhāntas, the latter both with and without the bija. The bija, which came into general Use about A.D. 1500, made no change in the length of the solar year or the number of civil days in a mahayuga, or in the position of the sun's apsis, and therefore none in the sun's longitude, whether true or mean. I shall attempt hereafter to publish similar Tables for the other principal Indian authorities-Tables which will be of great value in the verification of dates, seoing that up to the present time no one knows exactly at what periods and in what tracts these other Siddbäntas were used. (The Siddhanta-Siromani Table has been completed and is ready for Press.)
237. Assuming, since these Tables are not intended for any but the initiated, that the In lian Calendar process of calculation, which might be termed Prof. Jacobi's first process and which has the advantage of simplicity, is known to readers of the Epigraphia, only one or two remarks need be made before entering on details. Since everything depends on the accuracy of the Table-entries, I must call attention to the great help which I received from M. Louis de Ries of Moscow for many months. He takes the greatest interest in Hindu astronomy, and has prepared certain Tables of his own, the publication of which has been delayed by the War. His processos are characterized by the most laborious and painstaking endeavours to obtain extreme accuracy for every result arrived at. Filled with a similar desire, and after my calculations for the gun's exact position (in true longitude for saccessive 24-hour periods after the true sun's arrival at long. 0°) had been carried out for about one-third of the Arya-Siddhānta year, I asked M. de Ries to calculate some of these positions of the sun by his own method, so that we might compare the resulte. He most kindly did so; and, when I state that our results, worked in entire independence of one another and by different methods, were found to agree in every respect down to four, and in one case even down to five, decimals of a second, I think that it may be fairly assumed that my Tables may be depended upon,
238. There is more than one reason why the Indian Calendar system, though yielding results very fairly approximate, requires some expansion for the purpose of exact calculation, By it we have been in the habit of computing the true moon's place both for the tithi and nakshatra by the Sürya-Siddhanta data, using the same figures for finding the tithi-index, t, and nakshatra-index, n, for all dates, both for inscriptions known to belong to tracts and times when the Arya-Siddhanta was the authority used by the framers of the record, as well as for those which must have been guided by almanacks calculated by the Surya-Siddhānta. The e of the Indian Calendar method, i.e. the sun's mean anomaly at any moment, is always the Sürya-Siddhanta o in thousandths of the circle, and that it differs in various proportions at different times of the year from the c of the Arya-Siddhanta will be apparent to anyone who compares the entriee for the same day given in my new Tables XLVIIIA and B, cols. 2, 3, in ten-thousandths. At the moment of Mēsha-samkranti for instance (the first entry in each Table) the c by the Sürya is 2794.0642 in ten-thousandths, and is 279 in thousandths in Indian Calendar reckoning; but by the Arya-Siddhanta it is 27745577, and so for our ordinary reckoning should be stated as 277. In caloalation for the tithi-index, t, in ordinary work this difference has no very great effect, though of course it actually has some, and possibly may in some cases alter the value of t by one unit (47 minutes); but it has greater effect when we are calculating the nakshatra, as will presently be explained. As to the difference between the two authorities in the value assigned to the sun's true longitude, #, it will be seen that this varies day by day. About Day 261, i.e. the 261st period of 24 hours eacb measured from