The Five Astronomical Canons

and that stanzas 8-13 of the third chapter add certain details which were peculiar to the former of the two SiddhântasA Sanskrit term for a comprehensive astronomical treatise or "established conclusion.". It is greatly to be regretted that the introductory stanza of chapter II, which possibly would throw some light on the position of the chapter, has remained altogether obscure to us.

There now remain for adjudgment only the first and the last chapters of the Pañchasiddhântikâ The "Five Astronomical Treatises" composed by Varâha Mihira.. The latter I shall discuss further on. The position of the former is altogether clear; it contains, subsequently to some introductory stanzas, a rule for calculating the aharganaThe "heap of days"; the number of elapsed days from a fixed epoch to a given date. according to the Romaka Siddhânta The "Roman" or "Greek" astronomical system., an exposition of the principles according to which the intercalation of lunar months and the omission of lunar days are managed in the Pauliśa, Romaka and Sûrya Siddhântas, and finally a set of rules for calculating the so-called Lords of the year, month etc., which rules were most likely given in each of the three Siddhântas last mentioned.

The second question, which must be touched upon before we can review the teaching of the individual Siddhântas, is whether the Pañchasiddhântikâ represents the teaching of the five astronomical works, on which it is professedly based, with absolute accuracy, or rather allows itself certain modifications of the doctrines summarized. This question is one of considerable importance; for before we have settled it one way or other, we are unable to judge of the historical position of the five Siddhântas, and to compare the account, given of them by Varâha Mihira, with what we know about them from other sources. We have, in this part of our investigation, to occupy ourselves almost exclusively with the Sûrya Siddhânta The "Treatise of the Sun," one of the most influential Indian astronomical texts., because that treatise is the only one of the five Siddhântas which has come down to our time, and thus allows of our comparing it with what Varâha Mihira tells us about the Sûrya Siddhânta as known to him. Now a cursory survey of those chapters of the Pañchasiddhântikâ which treat of the Sûrya Siddhânta shows at once that the treatise of that name known to Varâha Mihira agreed with the modern Sûrya Siddhânta in its fundamental features. The methods of the two treatises are essentially the same and, on the other hand, sufficiently different from those of the other Siddhântas summarized by Varâha Mihira, to ensure to the Sûrya Siddhânta in its two fold form a distinct position of its own. At the same time we cannot fail to notice that in certain points the teaching of the old Sûrya Siddhânta (by which name I shall, for shortness sake, designate the Sûrya Siddhânta known to Varâha Mihira) must have differed from the correspondent doctrines of its modern representative. If we, for instance, observe that the old Sûrya Siddhânta assigned to the mean diameters of sun and moon the values 32' 5" and 30' 54" (P. S. IX. 15. 16), while 32' 3."6 and 32' are the corresponding values according to the modern