[ 3971 The exact amount of the ayanamsa may be apparently determined in different ways. Ist. The Siddhántas furnish a rule for computing it, which is in principle the same as the method of finding the longitude of a star at any given date by applying the amount of precession to its longitude, at some other date. 2nd. Defining the initial point with the belp of other data, such as the recorded longitudes of stars, its present longitude from the equinoctial point may be ascertained. 3rd. Knowing the exact year when the initial point was fixed, its present longitude (ayanánſa) may be calculated from the knowo rate of procession. But it so happens that the results obtained by these three methods do not agree. To begin with the first method. It will be seen that the different Siddhántas do not agree, either in the nature of preces sional movement, or in its annual rate. According to sorbe, the equinoxes have an oscillatory motion, turning to the right and to the left of the initial point within certain limits, and extending over a large interval of time; while others maintain their continuous motion backwards. Colebrooke compared the views of the libration and revolution theorists, and gave the rate of precession according to each. They are as follows : Libration Theory, Annual Rate, Súrya-Siddhanta Soma* Sakalya Laghu-Vašishtha. 54" Ranganatha, in his commentary to the Surya-Siddhanta, quotea Boxa- Siddhanta in support of the rading चिंत्यो युग भानाम् । Digitized by Google
