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

203 ximate statement just like saying that ‘Since 12 Rasis rise in the course of a sidereal day, so each rasi rises in 1800 asus’ which is far from truth being based on a crude rule of three. So, Bhāskara says, Acharyas like Aryabhata insisted on finding the rising times of Dṛkkāṇas, in as much, as while computing the Lagna or the point of inter- section of the Ecliptic with the horizon, we will be nearer the truth by using the rising times of smaller arcs like Dṛkkāṇas than broadly using those of Rasis. Verse 61. Bhujāntara correction. The equation of centre of the Sun multiplied by the equatorial rising time of the Rāsi occupied by the Sun, and divided by 1800, and then again multiplied by the true daily motion of a planet and divided by the number of asus in a day, is the correction in the planet positive or negative according as the equation of centre of the Sun is positive or negative. Comm. This Bhujāntara correction arising out of the Sun’s equation of centre is prescribed even for the Sun, as well as for the other planets. The planets are originally computed for the rising time of the Mean Sun, whereas we are interested to know the positions at the True Sun- rise. The position of the Sun also is originally computed for his mean rise and is therefore to be rectified to get his position at his true rise. So even the Sun is not exempt from the correction. It will be noted here that as the equation of centre pertains to the eccentricity of the Sun’s orbit, this correction of Bhujāntara is a correction for the so-called modern ‘Equation of time due to eccentricity’. In other words, the Sun’s equation of centre converted into time is exactly what is called the Equation of time due to eccentricity. The formula prescribed for the correction is as follows. Suppose the Sun is in a particular Rāsi which rises at the equator in x asus. Let the equation of centre of the Sun be