ब्राह्मस्फुटसिद्धान्त (ब्रह्मगुप्त - शून्य, कुट्टक, बीजगणित एवं सम्पूर्ण २१ अध्याय सान्वय सटीक)

304 BRAHMAGUPTA'S ASTRONOMY : ITS HIGHLIGHTS of the Sun and the Moon without basing on ahargaṇa has also been given by Brahmagupta in the Khaṇḍakhādyaka¹. Concordance of Working Rules There has been a good deal of agreement on various rules of astronomical constants from the time of Āryabhaṭa I (499 A. D.) to the Bhāskara II (1150 A. D.) or even later to the days of Munīśvara (1620 A, D). Earliest concepts were formulated during the days of the Vedāṅga-Jyautiṣa and the Siddhāntas of Indian and the western origin, for example of Brahma, Vasiṣṭha, Pitāmaha, Romaka and Puliśa. We in this section are giving some important concordances which we find common in the writings of Brahmagupta and his predecessors, contemporaries and successors as listed below. The list is not exhaustive. Only a few illustrations have been cited.

1. Ārya.—Āryabhaṭīya, Āryabhaṭa I, 499 A. D.
2. BrSpSi. —Brāhmasphuṭasiddhānta, Brahmagupta, 628 A. D.
3. K. K.—Khaṇḍakhādyaka, Brahmagupta, 628 A. D.
4. KKu.—Karaṇa-kutūhala, Bhāskara II, 1150 A. D.
5. LBh.—Laghu-Bhāskarīya, Bhāskara I, 522 A. D. MBh.—Mahā-Bhāskarīya, Bhāskara I, 522 A. D. MSi.—Mahā-siddhānta, Āryabhaṭa II, 950 A. D. PSi.—Pañcasiddhāntikā, Varāhamihira, 505 A. D. ŚiDVṛ.—Śiṣyadhīvṛddhida, Lalla, 598 A. D. SiSā.—Siddhāntasārvabhauma, Munīśvara, 1620 A. D. SiŚe—Siddhāntaśekhara, Śrīpati, 1039 A. D. SiŚi.—Siddhānta-Śiromaṇi, Bhāskara II, 1150 A. D. SuSi.—Sūryasiddhānta, Modern, 6th or 7th Century.
6. Rule for finding the mean longitudes of the Sun, Mercury and Venus : BrSpSi. I. 44. Also MBh. 1. 31. MSi I. 26 ; SiŚe II. 42, 43 ; SiŚi. I i. (d). 15 ; SiSā I. 105 ; KKu I. 7.
7. Rule for finding the mean longitude of the Moon's ascending node : BrSpSi, XXV. 35.
8. दिनदलभक्तमवमावशेषभाप्त दिनादि तत्सहितान् । अधिमासशेषाकाञ्च त्रिंशद् गुणितादृ‌तुखदिग्भिः ॥ मासदिन प्रथमैक्यं पृथक् त्रयोदशगुणं द्वितीयोनौ । द्वाक्येवं भृव्यौ राश्याद्यवार्कचन्द्रौ वा ॥ =KK. I. 11–12