the earth's surface (bhagola-prstha). The last will give the True Position (sphuta) of the planets as seen by an observer stationed on the surface of the earth.
Born into the live astronomical tradition of the land and being, in himself an investigator, Acyuta has been responsible for initiating fresh lines of thought and introducing new calculations intended for better results, including the formula for the "Reduction to the ecliptic,” mentioned earlier. He noticed the fallacy, in the then current astronomical practice, of measuring the positions of all the planets as if they moved along the ecliptic (the Sun's path), while, in fact, they moved along their own different orbits (ksepa-vritta-s), each of which deviated slightly from the ecliptic. He argued that if the computed positions of the planets were to be accurate, the said deviation of their orbits should also be taken into consideration and adequate correction applied to their measurements on the ecliptic. Thus, he says in his Raśigolasphutānīti, verses 44 ff. :
|
चन्द्रादयः क्षेपवृत्ते भ्रमन्ति सततं यतः । |
On the basis of appropriate calculations in this regard, he enunciated in Sphutanirnaya 4.2, a detailed formula for the reduction of the Mean Moon to the ecliptic, a formula which could be extended to the other planets as well. It deserves to be noted that this formula agrees remarkably well with that enunciated in the West by Tycho Brahe and used in later computations. While the present publication is restricted to a critical edition of the Sphutanirnaya and its commentary, a translation of the work with a detailed analysis of the rationale of the several formulae and computational procedures depicted the rein is to follow, in due course.
1. On this subject, see K.V. Sarma, A history of the Kerala school of Hindu astronomy, Hoshiarpur, 1972, pp. 1-6.
2. For an analysis of Acyuta's formula and its corre'ation with its modern counterpart, see K. V. Sarma, Radigolasphufaniti of Acyuta, ed. with trans. Adyar Library and Res. Centre, Adyar, Madras-(, Introduction, pp. 7-4.
