Bharatiya Jyotihshastra (History of Indian Astronomy), translated by R. V. Vaidya v1.c5.71

v1.c5.71

The quest of knowledge regarding such matters led to the creation of three branches. The following questions, for instance, are associated with Mathematics (Gaṇita): Finding out the number of days in a month, the number of months in a year and the number of days in a year; when will the winter solstice or the summer solstice occur after a particular day; what position in the sky will a particular planet be occupying on a certain day; when will an eclipse take place, and so on. These questions are related to Mathematics. The knowledge of the effects of eclipses, comets, planetary conflicts on the world and the knowledge as to what days are auspicious or otherwise for the performance of marriages and other rites—these questions form the second branch; and the third branch comprises the knowledge which enables one to judge the benefic or malefic effects that would be produced by a particular position of planets at birth or later on in the life of an individual. These are said to be the ‘Three Branches’ (Triskandha) of astronomy.