Epigraphia Indica Vol 14

Author(s): Sten Konow, F W Thomas
Publisher: Archaeological Survey of India

Page 21

EPIGRAPHIA IXDICA.
[Vol. XIV.
Thus the real nakshatrn-index, 16, was 9338, and our Imlian Calendar process with result 9328 yielded a result in error by 10 units, or 39 minutes of time.
(ii) By the Sürya-Sildhinta.-By Tablo XLVIITB, col. 3, we havo the sun's mean anomaly c at 12 h. 44 m. after mean sunrise = 3341-6212, in ten-thousandths of the circle. Deduct for 12 h. 13-6839 and for 44 m. 0-8365 (Tallo XLIV) for the sun's inean motion, total 14-5254.3341.6212 - 14-5254 = 3327-0958. This was the sun's mean anomaly at mean sunrise. Calling this 333 and consultiug Indian Calon lar Table VII, we should raise equation o in our original work from 7 to 8.
Again we test this by the more accurate process. The equation of the centre on the given day 12 h. 44 m. after mean sunrise was (Table XLVIIIB, col. 7) 52-3475. The same for the previous day was 52-8500. Difference = 0-5025. Divided by 24, this gives an average difference per hour of 0.02094. Taking 12 b. 44 m. as 13 h. and multiplyiny, we have 0.27224. Add 0.2722 to the equation of the day, 52-3475, and we find as the equation of the centre at mean suprise 52 6197. 604-526179 = 77803. Hence equation in the original calculation should certainly have been 8, and not 7.
Lastly we substitute the newly found values as before, for Indian Calendar calculation, &, having been already determined to have been at mean sunrise by this authority 526-2164.
a Equation b Equationc
. . .
8541 260
7.7803
Add
8808-7803 526-2164
s =
.
9334.9967 say 9335.
This is as near as we can get to the true nakshatra-index at mean sunrise. It differs by 7 units from the Indian Calendar value, which was 9328, or by 28 minutes of time.
(iii) Allowance for the shift in the sun's perigee-point when working by the Sürya-Siddhānta.--I have shown below ($ 254) that, for calculation of the tithi, Dakshatra, or lagna, this shift in the apsis may well be ignored; but in case any one should desire to take notice of it I have entered a Table (p. 12 below), giving its exact amount. Its effect on our inscription-date is as follows. Tablo XLVIIIB is calculated for about A.D. 1400. The year of our inscription is A.D. 1490. 90 years after A.D. 1400 the perigce-point had advanced (see Table) 0.0806 from the position we 8.88 u med for it. Hence the sun's mean anomaly at mean sunrise of our date was not, as already found, 33270958, but this amount less 0·0806, or was actually at 3327-0152. 90 years earlier than A.D. 1400 it would have been 3327095% plas 0.0806, or 3327-1764. But this change would have only an infinitesimal effect on the equation of the centre, or, in consequence, on the sun's true longitude, or on the calculated values of the tithi, nakshatra, or lagna.
0. The Yoga, by either Siddhanta.-The formuln for this is 2 s+t, and, as the value of s has been correctly found by the above process, no further remark is necessary.
D. The lagna, (1) by the Arya-Siddhānta.-For this we have to find the correct value of . at mean sunrise in degrees, etc. By Table XI.VIILA, col. 6, the s for the day was in oor