AHARGANA 5. above process may sometimes be in excess or defect by one. To test whether the ahargana (obtained by the above process) is correct, it is divided by seven and the remainder counted with Friday. If this leads to the day of calculation, the ahargana is correct; if that leads to the preceding day, the ahargana is in defect; and if that leads to the succeeding day, the ahargana is in excess. When the ahargana is found to be in defect, it is increased by one; when it is found to be in excess, it is diminished by one. Similarly, when a true intercalary month has recently occurred prior to the given lunar month or is about to occur thereafter, the true lunar month may differ from the mean lunar month by one. When a true intercalary month has occurred prior to the given month and the intercalary fraction amounts to one month approximately, then the whole number of mean intercalary months obtained in the above process is increased by one.¹ When no intercalary month has occurred prior to the given month but the intercalary fraction is small enough, the whole number of mean intercalary months obtained in the above process in diminished by one.² The word tithi in verse 4 stands for 30. It is generally used to denote the number 15. An alternative rule: 7. Or, multiply the number of (solar) months elapsed (since the beginning of Kaliyuga) by the number of lunar months (in a yuga) and divide by the number of solar months (in a yuga). Reduce the quotient to days (and add the number of lunar days elapsed since the beginning of the current lunar month); then multiply by the number of civil days (in a yuga) and divide by the number of lunar days (in a yuga); the quotient denotes the ahargana.³ The number of solar months elapsed since the beginning of Kaliyuga is equal to the number of mean solar months lying between K and S. 1 "If the current lunar month is preceded by an intercalary month, then that intercalary month should also be treated as a lunar month." (Parameśvara). ² Cf. Siśi, I, i (f). 3. ³ The same rule occurs also in BrSp.Si, xiii. 18 and Sise, ii. 3.
