Bharatiya Jyotihshastra (History of Indian Astronomy), translated by R. V. Vaidya v2.c12.s10.4

v2.c12.s10.4

This chapter describes the calculation of the conjunction of planets with the junction-stars of nakṣatras and for this purpose lists of polar longitudes and latitudes of junction-stars and of some other stars are given. The figures denoting longitudes are generally corrected by “*ayana-dṛk-karma-saṃskṛta*” *i.e.* they are governed by the following conventional definition. ‘BHOGA’ (*longitude*) is the ecliptic arc between the initial point and the point where the perpendicular drawn from the star to the celestial equator cuts the ecliptic and the ŚARA (*latitude*) is the distance of that point from the star. Let us call such longitudes and latitudes, polar longitudes and latitudes. The longitudes and latitudes in certain works conform to this definition. BHOGA (longitude) is the ecliptic arc between the initial point and the point where the perpendicular drawn from the star to the ecliptic cuts the ecliptic : and the perpendicular so drawn is the Śara (latitude). The pole of the ecliptic is also known as Kadamba. Let these longitudes and latitudes be, therefore, called 'KADAMBĀ-BHIMUKHA' (facing the pole, *kadamba*). On pages 338 and 339, later on, have been given the polar latitudes and longitudes of stars, as given in six works. The polar longitudes and latitudes of those* stars which in the author's opinion, should be regarded as junction-stars are also given. The correction due to 'ayana-dṛk-karma' is not always the same owing to the shifting of the eqinoxes. Hence the polar longitude of a star will not always remain the same. It may be partly due to this reason that the longitudes of stars mentioned in six works, which have been given below differ from one another to a certain extent ; some differences may be due to the fact that different stars might have been adopted as junction-stars. The *dhruvas* (polar longitudes and latitudes) mentioned by the Sūrya-Siddhānta, Brahmagupta Siddhānta and Lalla Tantra, belong to a period when the amount of ayanāṃśa was exceedingly small. About this BHĀSKARĀCĀRYA remarks :