Page:Sewell Indian chronography.pdf/102
Example 11.—To find the moment of any true sidereal saṁkrāntis by the Ārya Siddhānta.
Each saṁkrānti marks the astronomical beginning of the solar month which takes its name, being the moment when the sun in his course, measured by his apparent longitude, enters a sign.
Rule. Find the moment of true Mēsha saṁkrānti by the Ārya Siddhānta for the given year from Table I., or, for years earlier than A.D. 300, by Example 3. Add to it the collective duration given in cols. 3 or 4 of Table XVIII.A from that moment to the given saṁkrānti. (§ 59.)
Wanted the time of Vṛiśchika saṁkrānti according to the Ārya Siddhānta in K.Y. 4321 expired, A.D. 1220—21
| d. | w. | h. | m. | |
| (Table I.) M.S. for the year | 24 March (84) | 3 | 14 | 40 |
| (Table XVIII.A) Coll. Dur. to Vṛiś. saṁk. | (216) | 6 | 19 | 6 |
| Vṛiśchika saṁkrānti | (301) | 3 | 9 | 46 |
301 = (Table IX.), A.D. 1220 being a Leap-year, Oct. 27th. 3 = Tuesday.
Answer. Tuesday, October 27th, A.D. 1220, at 9 h. 46 m, Laṅkā time, i.e., measured from mean sunrise.
Example 12.—The same by the Sūrya Siddhānta.
Rule. Find the time of true Mēsha saṁkrānti according to the Sūrya Siddhānta from Table I., or by Examples 1 or 4. Add the collective duration to the given saṁkrānti as given in cols. 3 or 4 of Table XVIII.B.
Wanted the time of Vṛiśchika saṁkrānti according to the Sūrya Siddhānta in K.Y. 4321 expired, A.D. 1220–21.
| d. | w. | h. | m. | |
| (Table I.) M.S. for the year | 24 March (84) | 3 | 15 | 59 |
| (Table XVIII.A) Coll. Dur. to Vṛiś. saṁk. | (216) | 6 | 19 | 54 |
| Vṛiśchika saṁkrānti | (301) | 3 | 11 | 53 |
Answer. Tuesday, October 27th, A.D. 1220, at 11 h. 53 m, Laṅkā time. (Compare with Example 11.)
Example 13.—To convert the time of any true saṁkrānti as found by the Ārya Siddhānta into the same according to the Sūrya Siddhānta.
Table XVIII.C has been framed to enable this to be done.
Rule. The time by the Ārya Siddhānta being given, apply to it Corrections I. (Table XVII.) and II. (Table XVIII.C), both Tables as they stand. (§§ 46, 56.)
E.g., Wanted the time of true Vṛiśchika saṁkrānti by the Sūrya Siddhānta in the same year as in Examples 11, 12, its time according to the Ārya Siddhānta being October 27th A.D. 1220, at 9 h. 46 m.
| h. | m. | ||
| Correction II.I. (Table XVII.) | + | 1 | 19 |
| Correction II. (Table XVIII.C) | + | 48 | |
| 2 | 7 |
9 h. 46 m. + 2 h. 7 m. = 11 h. 53 m.; and this was the exact time as found in Example 12.
Example 14.—To convert the time of any true saṁkrānti as found by the Sūrya Siddhānta into the same according to the Ārya Siddhānta.
Rule. The time by the Sūrya Siddhānta being given, apply to it Corrections I. and II. with signs reversed. (§§ 46, 56.)