Page:Sewell Dikshit The Indian Calendar (1896) proc.djvu/44
Madhyaś Chândro mâso madhyâdhika-lakshaṇam chaitat ‖
Vidvâṁsas-tv-âchâryâ nirasya madhyâdhikam mâsaṁ
Kuryuḥ sphuṭa-mânena hi yato 'dhikaḥ spashṭa eva syât. ‖
"The lunar month which has no mean sun's entrance into a sign shall be a mean intercalated month. This is the definition of a mean added month. The learned Âchâryas should leave off [using] the mean added months, and should go by apparent reckoning, by which the added month would be apparent (true)."
It is clear, therefore, that mean intercalations were in use up to Śrîpatis time. In the Vedâṅga Jyotisha only the mean motions of the sun and moon are taken into account, and it may therefore be assumed that at that time the practice of regulating added and suppressed months by apparent motions was unknown. These apparent motions of the sun and moon are treated of in the astronomical Siddhântas at present in use, and so far as is known the present system of astronomy came into force in India not later than 400 A. D.[1] But on the other hand, the method of calculating the ahargana (a most important matter), and of calculating the places of planets, given in the Sûrya and other Siddhântas, is of such a nature that it seems only natural to suppose that the system of mean intercalations obtained for many centuries after the present system of astronomy came into force, and thus we find Śrîpati's utterance quoted in an astronomical work of the 15th century. There can be no suppression of the month by the mean system, for the mean length of a solar month is longer than that of a mean lunar month, and therefore two mean saṅkrântis cannot take place in a mean lunar month.
The date of the adoption of the true (apparent) system of calculating added and suppressed months is not definitely known. Bhâskarâchârya speaks of suppressed months, and it seems from his work that mean intercalations were not known in his time (A. D. 1150.) We have therefore in our Tables given mean added months up to A. D. 1100. and true added and suppressed months for the whole period covered by our Tables.[2]
48. For students more familiar with solar reckoning we will give the rules for the intercalation and suppression of months in another form. Ordinarily one lunar month ends in each solar month. When two lunar months end in a solar month the latter of the two is said to be an adhika (added or intercalated) month, and by the present practice it receives the name of the following natural lunar month, but with the prefix adhika. Thus in the Table on p. 25, two lunar months end during the solar month Mesha, the second of which is adhika and receives, by the present practice, the name of the following natural lunar month. Vâiśakha. When no lunar month ends in a solar month there is a kshaya mâsa, or expunged or suppressed month; i.e., the name of one lunar month is altogether dropped, viz., by the present practice, the one following that which would be derived from the solar month. Thus, in the Table above, no lunar month ends in the solar month Dhanus. Mârgaśirsha is the name of the month in which the Dhanus saṅkrânti occurs; the name Pausha is therefore expunged.
The rule for naming natural lunar months, and the definition of, and rule for naming, added
- ↑ Up to recently the date was considered to be about the 6th century A.D. Dr. Thibaut, one of the highest living authorities on Indian Astronomy, fixes it at 400 A.D. (See his edition of the Pañcha Siddhântikâ Introd., p. LX.). My own opinion is that it came into existence not later than the 2nd century B.C. [S. B. D.]
- ↑ I am inclined to believe that of the two rules for naming lunar months the second was connected with the mean system of added months, and that the first came into existence with the adoption of the true system. But I am not as yet in possession of any evidence on the point. See, however, the note to Art. 51 below. [S. B. D.]