Bharatiya Jyotihshastra (History of Indian Astronomy), translated by R. V. Vaidya v2.c12.s2.t2.6

v2.c12.s2.t2.6

The oldest known works on astronomy are the five Siddhāntas—the Sūrya Siddhānta and others. These are regarded as divine. They are again of two kinds. The Pañcasiddhāntikā of Varāhamihira mentions the Saura and other four Siddhāntas ; but at present they are not available. The Pañcasiddhāntikā simply provides clues to their elements. The author calls them the ‘ancient Siddhānta Pañcaka’ or ‘group of five ancient Siddhāntas’. There are five other Siddhāntas likewise entitled the Saura, which are at present available. He calls them ‘the modern group of five Siddhāntas’. These will presently be dealt with. First he takes up for consideration the group of five ancient Siddhāntas. These belong to the 5th century before Śaka era. Some of them may belong to an even earlier period.