The identification of nakshatra junction stars from precession calculations

Abstract

The names of the nakshatras along with the longitudes of their junction stars are found in various ancient Indian texts on astronomy. But identification of the appropriate junction stars associated with the nakshatras has been a problem for a long time. Various suggestions have been made to reconcile modern catalogue stars with nakshatras, but they have not been universally accepted. Moreover, the longitudes of the junction stars change due to precession of the Earth’s equinox, which is 50.3 arcseconds/year. There is a list of 27 nakshatras along with the longitudes of their junction stars given in the Maha Bhaskariya. By comparing those longitudes of the junction stars with their present longitudes and considering a precession of nearly 20°, the appropriate junction star for each nakshatras can be identified. Most of the junction star names proposed by Abhyankar in fit perfectly according to our calculations, except for a few nakshatras: Asvini, Adra, Visakha, Satabhisak and Purva-Bhadrapada.