Bharatiya Jyotihshastra (History of Indian Astronomy), translated by R. V. Vaidya v1.c5.92

v1.c5.92

*Siddhānta* or *Tantra* generally consists of two parts, one mainly deals with the calculation of planets’ places and the other chiefly describes the structure of the universe ; and this includes the knowledge of the celestial sphere, the construction of instruments, the units of the measurement of time and other allied subjects. These two parts are not and cannot remain separate, Almost all *Siddhāntas* show as an intermingling of the two. Some people define *Siddhānta*, *Tantra* and *Karaṇa* in the following way :—