Brahmasphutasiddhanta (Complete Sanskrit Text)

The equinox moves westward by approximately one degree in sixty-five years; because such knowledge is seemingly impossible to attain in a short time, it appears that Brahmagupta, even as an expert in observation, did not discover the precession of the equinoxes. Although he was an opponent of Āryabhaṭa, Brahmagupta composed a work called the Khaṇḍakhādyaka thirty-seven years after the composition of the Brahmasphuṭasiddhānta, as he states at the beginning:

From a review of this book, it is known that it was extremely difficult to eradicate the view of Āryabhaṭa that was prevalent among the people who practiced it. Brahmagupta composed the practical manual called Khaṇḍakhādyaka for the benefit of contemporary people who followed Āryabhaṭa's system. Just as the Brahmasphuṭasiddhānta is the ideal text among the ancient available astronomical treatises, the Khaṇḍakhādyaka, which is thirteen hundred years old, is the original ideal among all practical manuals. Now, as Bhāskara says in his Bījagaṇita Algebra, "The mathematical seeds of Brahmagupta, Sridhara, and Padmanabha are very extensive," it is known that Brahmagupta had an extensive algebra book, but this book is neither found anywhere nor heard of. Brahmagupta himself is the ideal for Shripati above all others. A review of the Brahmasphuṭasiddhānta and the Siddhāntaśekhara shows that the brief, meaning-rich āryā verses spoken by Brahmagupta were translated by Shripati into large-form meters. In reality, Shripati, having understood the subtle planetary mathematics stated by Brahmagupta and accepting them as truth, composed an easier alternative book (Siddhāntaśekhara) by removing the discrepancies in his statements; there is no dispute about this. Regarding the composition of the book, Lallācārya was the ideal for Shripati. Whatever topics were not mentioned by Brahmagupta but were mentioned by Lalla, Shripati certainly stated them in the same way using different verses. In reality, Shripati composed the Siddhāntaśekhara after studying both books (Brahmasphuṭasiddhānta and Śiṣyadhīvṛddhida). A little consideration is given to the names of the teachers that have appeared in the Brahmasphuṭasiddhānta. The Brahmasiddhānta is the earliest of all treatises, or the most ancient; it is also called Pitāmahasiddhānta Treatise of the Grandfather/Brahma by some. In the Pañcasiddhāntikā, Varāhamihira mentioned the Paitāmahasiddhānta, consisting of five āryā verses in the twelfth chapter: