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

141 equation of centre pertaining to the planet which may be taken to be equal to 2e as a first approximation where e is the eccentricity of the elliptic orbit of the planet. It may be further mentioned here that in Sūrya- siddhānta, as well as elsewhere in this work, the circum- ferences are given to vary continuously. This variability curiously achieves ellipticity in the orbit as may be seen as follows. In the case of the Sun, the epicycle has a periphery of 14° when m = 0 or 180° and of 13 ⅔° when m = 90° or 270 according to Sūryasiddhānta, where m is the Manda- kendra or mean anomaly. At any arbitrary point, where Fig. 10