Brahmasphutasiddhanta (Complete Sanskrit Text)

The absence of its [the Pāta] effect is also mentioned in cases of travel, marriage, etc., by saying, "Again, the three days here are not harmful." By this, it is stated that, in effect, as long as the solar disc, in the manner of the tuhinākara Moon (along with the Moon’s corrected declination), remains on one path for a period of time (on one diurnal circle, meaning until the distance between the two declinations is half the sum of their diameters, such that the declination of a portion of the discs becomes equal), the sages who predict fruits have spoken of the possibility of the effect arising from the Pāta. In the absence of that Sun and Moon remaining on one path together with their corrected declinations, the absence of that effect also occurs.

Here again, during the time of the Pāta, the three days are not harmful for auspicious acts like travel and marriage. In some books of results, it is said by some that when Vyatīpāta and Vaidhṛta specific astrological conjunctions occur, that day, the day before it, and the day after it—a total of three days—are prohibited for auspicious works; to refute that, he says "the three days are not harmful." In the Sūrya Siddhānta and other works, the fault in auspicious acts exists only during the time of the Pāta; when the time of the Pāta has passed, there is no fault. By occasion, a reference to the Siddhāntaśekhara Crest of Doctrines has been made here, since Śrīpati Ācārya is later than Brahmagupta. His name is not mentioned in the Brahmasphuṭasiddhānta.

Among Indian astronomers, Āryabhaṭa was the first to explain the cause of day and night as the rotation of the Earth. In the first verse of the Gītikāpāda Chapter of Songs, having first stated that there are 4,320,000 revolutions of the Earth in one Mahāyuga Great Age, totaling 1,582,237,500 [rotations], he confirms the rotation of the Earth through an illustration:

By this, he confirms it. But it is strange to observe here that the commentator of the Āryabhaṭīya, Parameśvara, commented on this verse: "Some wish for the Earth's forward motion and the absence of motion of the stars; that is born of false knowledge, accepting the perception of westward motion and calling it the Earth's forward motion. In reality, the Earth is stationary." Even Āryabhaṭa himself seems to reject the Earth's rotation by saying:

There was no certainty in Āryabhaṭa's mind whether the Earth moves or does not move. Brahmagupta proposed an unprecedented concept, natakarma inclination correction. The planet that results from the processing of mandaphala slow/apsidal correction, śīghraphala fast/conjunction correction, and bhujāntara difference of the base is the "computed planet," but the planet that appears to us where it is visible is the one that deserves to be our "apparent planet." The correction by which our apparent planet becomes the one appearing in its own sphere is the very name of the correction, natakarma. Before Brahmagupta, no ancient teachers mentioned this (natakarma).