Page:English translation of the Surya Siddhanta and the Siddhanta Siromani by Sastri, 1861.djvu/19

 From the number of these elapsed days, the Rulers of the present day month and year can be known (by reckoning the order of them) from the Sun.

Divide the number of elapsed terrestrial days by 7, and reckoning the remainder from the sun-day, the Ruler of the present day will be found.

. Divide the number of elapsed terrestrial days by the number of days in a month and by that in a year (i. e. by 30 and 360) multiply the quotients (rejecting the remainders) by 2 and 3 respectively, and increase the products by 1. Divide the results by 7, and reckoning (the order of the Rulers) from the Sun, the remainders will give the Rulers of the present (terrestrial) month and year respectively. lunar months, &c., considering them as solar, be added: the sum is the elapsed solar months up to the time when the Sun enters the stellar sign of the Zodiac corresponding to the present lunar month. To make these solar months lunar, let the elapsed additive months be determined by proportion in the following manner.

If these additive months with their remainder be added to the solar months elapsed, the sum will be the number of lunar months to the end of the solar month; but we require it to the end of the last lunar month. And as the remainder of the additive months lies between the end of the lunar month and that of its corresponding solar month, let the whole number of additive months, without the remainder, be added to the solar months elapsed; and the sum is the number of the lunar months elapsed to the end of the last lunar month. This number of lunar months elapsed, multiplied by 30 and increased by the number of the passed lunar days of the present lunar month, is the number of lunar days elapsed. To make these lunar days terrestrial, the elapsed subtractive days should be determined by proportion as follows.

If these subtractive days be subtracted with their remainder from the lunar days, the difference will be the number of terrestrial days elapsed to the end of the last lunar day; but it is required to the present mid-night. As the remainder of the terrestrial days lies between the end of the lunar day and the mid-night, the whole number of the subtractive days, (without the remainder) should be subtracted from the lunar days elapsed, and the difference is, of course, the number of terrestrial days elapsed from the time, when planetary motions commenced, to the present mid-night at. B. D.