Indian Epigraphy: A Guide to the Study of Inscriptions in Sanskrit, Prakrit, and the Other Indo-Aryan Languages c10.s3.t3.11

c10.s3.t3.11

*siddhānta*, *Ārya-siddhānta*, etc.) was used to calculate the *tithi*, due to their differing solar models and parameters for the movements of the heavenly bodies; the moment of the expiry of a *tithi*, which is critical to calculations of dates, may vary by as much as an hour or even more according to different *pakṣas* (Jacobi, EI I, 403). It is therefore necessary to check results by the different systems in any case where the result is in doubt, for example, where the weekday calculated by the general system falls one day before or after the one specified in the document, or where the end of the astronomical *tithi* falls within three hours of sunrise.⁶⁰ Moreover, in calculating the date for a given inscription adjustments must always be made for the conversion of mean Laṅkā time as given in the tables to true local time according to the latitude and longitude of the place of issue, insofar as this is known (Jacobi, 412; cf. n. 53). Here, too, the variations between mean time and local time may affect the moment of the end of the *tithi* and thus produce a different civil date.