सिद्धान्तशिरोमणि: गणिताध्याय (भास्कराचार्य - ग्रहगणित, मध्यमाधिकार व स्पष्टाधिकार सटीक)

next Sun-rise, T₃ the ending moment of the tithi preceding the Sun-rise R₄ upto which point the Ahargaṇa has to be found from the commencement of the Solar year. Thus the Ahargaṇa to be found is SR₄ = ST₃ + T₃ R₄. Here T₃ R₄ is the Kshayāghatis, at the Sun-rise concerned. SR₃ is a fraction of a day that is to be there in the Ahar- gaṇa SR₄ we are seeking. While subtracting the Śuddhi T₁ S diminished by the Kshayāghatis T₂ R₃ from the number of elapsed integral number of tithis from the commencement of the luni-Solar year namely T₁ T₃ we have T₁ T₃ — (T₁ S — T₂ R₃) = T₁ T₃ — (T₁ T₂ — SR₃) = T₂ T₃ + SR₃. Thus instead of SR₃ + R₃ R₄ we have by the above procedure SR₃ + T₂ T₃. Though both T₂ T₃ and R₃ R₄ are integral numbers and should be the same if the interval is small, they may differ by an integral number, if the interval happens to be long. Bhaskara says that this difference of an integral number will be rectified by the Kshepadinas found under verse No. 12, for, from these Kshepadinas, the Kshayāhas are found and subtracted from the tithis. It will be noted that the difference of an integral number between T₂ T₃ and R₃ R₄ is no other than Kshayāhas. Or, this may be seen in an other way. We are to find SR₄ = T₁ R₄ — T₁ S = T₁ T₃ + T₃ R₄ — T₁ S = T₁ T₃ — (T₁ S — T₃ R₄) = No. of elapsed tithis — (Suddhi — Kshayaghatis at the day concerned). But instead of the Kshayaghatis at the day concerned Bhaskara prescribes the subtraction of the Kshayāghatis at the end of the Solar year ie instead of subtracting T₃ R₄ it is prescribed to sub- tract T₂ R₃. This difference, Bhaskara says is made up by taking into account the Kshepadinas pertaining to the Kshayāhas. Verse 14. In case the Ahargaṇa is required for a day preceeding the commencement of the Solar year, then the elapsed tithis are less than the Tithis of the Suddhi; so subtraction is not feasible. In this case, it is prescribed