Page:Sewell Dikshit The Indian Calendar (1896) proc.djvu/49

with reference to his mean motion. The cycle commences with Prabhava. See Table I., cols. 6, 7, and Table XII.

54. The duration of a Bârhaspatya samvatsara, according to the Sûrya-Siddhânta, is about 361.026721 days, that is about 4.232 days less than a solar year. If, then, a samvatsara begins exactly with the solar year the following samvatsara will commence 4.232 days before the end of it. So that in each successive year the commencement of a samvatsara will be 4.232 days in advance, and a time will of course come when two samvatsaras will begin during the same solar year. For example, by the Surya-Siddhanta with the bîja, Prabhava (No. 1) was current at the beginning of the solar year Saka 1779. Vibhava (No. 2) commenced 3.3 days after the beginning of that year, that is after the Mesha saṅkrânti; and Śukla (No. 3) began 361.03 days after Vibhava, that is 364.3 days after the beginning of the year. Thus Vibhava and Śukla both began in the same solar year. Now as Prabhava was current at the beginning of Śaka 1779, and Śukla was current at the beginning of Śaka 1780, Vibhava was expunged in the regular method followed in the North. Thus the rule is that when two Bârhaspatya samvatsaras begin during one solar year the first is said to be expunged, or to have become kskaya; and it is clear that when a samvatsara begins within a period of about 4.232 days after a Mesha saṅkrânti it will be expunged.

By the Sûrya-Siddhânta ⁠85+65/211⁠ solar years are equal to ⁠86+65/211⁠ Jovian years. So that one expunction is due in every period of ⁠85+65/211⁠ solar years. But since it really takes place according to the rule explained above, the interval between two expunctions is sometimes 85 and sometimes 86 years.

55. Generally speaking the samvatsara which is current at the beginning of a year is in practice coupled with all the days of that year, notwithstanding that another samvatsara may have begun during the course of the year. Indeed if there were no such practice there would be no occasion for an expunction. Epigraphical and other instances, however, have been found in which the actual samvatsara for the time is quoted with dates, notwithstanding that another samvatsara was current at the beginning of the year.^[1]

56. Variations. As the length of the solar year and year of Jupiter differs with different Siddhântas it follows that the expunction of samvatsaras similarly varies.

57. Further, since a samvatsara is expunged when two samvatsaras begin in the same year, these expunctions will differ with the different kinds of year. Where luni-solar years are in use it is only natural to suppose that the rule will be made applicable to that kind of year, an expunction occurring when two samvatsaras begin in such a year; and there is evidence to show that in some places at least, such was actually the case for a time. Now the length of an ordinary luni-solar year (354 days) is less than that of a Jovian year (361 days), and therefore the beginning of two consecutive samvatsaras can only occur in those luni-solar years in which there is an intercalary month. Again, the solar year sometimes commences with the mean Mesha-saṅkrânti, and this again gives rise to a difference.^[2]

The Jyotisha-tattva rule (given below Art. 59) gives the samvatsara current at the time of the mean, not of the apparent, Mesha-saṅkrânti, and hence all expunctions calculated thereby must be held to refer to the solar year only when it is taken to commence with the mean Meshasaṅkrânti.^[3] It is important that this should be remembered.