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

153 phala from the extremity of the Karna to the extremity of the radius in the deferent; but as this Karnānupāta is not adopted, the difference being negligible the quadrants are all of equal magnitude i.e. each of 90°. In the course of the commentary of this verse Bhāskara mentions that for Mercury, as the maximum S'īghraphala is 21°-31'-43", the quadrants are of magnitude 3-21-31-43, 2-8-28-17, 2-8-28-17 and 3-21-31-43 respectively. Also in the commentary Bhāskara adds that a₁ which is the point of intersectiou of the eccentric with the hori- zontal diameter E₁b₁ the S'īghraphala is maximum and that at that point the mean motion is itself the true motion “कक्षामध्यगतिर्यम्रेखाप्रतिवृत्तसम्पाते, मध्यैव गतिः स्पष्टा परं फल तत्र खेटस्य”. That the S'īghraphala at a₁ and a₃ is maximum is clear from the figure 13, where it is equal to the arcs b₁c₁ and b₂c₂ whose H sine is equal to r. To prove that the mean motion is itself the true motion, we have the equation M₂ + E₂ = S where M₂ is the mean planet here or the Mandasphutagraha or planet rectified for the equation of centre, (by the equation M₁ + E₁ = M₂, M₁ being the original mean planet and E₁ the equation of centre) so that δM₂ + δE₂ = δS where δM₂ is the mean motion here, δS the true motion and δM₂ is the variation in the S'īghraphala; but at a₁ and a₃ E₂ the S'īghraphala being maximum δE₂ is zero. Hence δM₂ = δS which means that the mean motion is itself the true motion. Verse 34. Latter half, 35 and 36 former half. The mean planet rectified for the equation of centre or Manda-phala is called Mandasphuta. Then subtracting the longitude of the Mandasphuta from that of the respective S'īghroccha, the result will be the S'īghra anomaly from which the S'īghra-phala is to be obtained. Rectifying the Mandasphuta for this second equation namely S'īghraphala, again obtaining therefrom the equation of centre effecting 20