Bharatiya Jyotihshastra (History of Indian Astronomy), translated by R. V. Vaidya v2.c12.s5.9.3

v2.c12.s5.9.3

but man must have acquired knowledge of astronomy in the initial stages, through the efforts of such persons ; and my object in relating such experiences is to show that the habit still persists among our people. Europeans are surprised to see that while the Saura, Ārya and Brahma siddhāntas mention the numbers of revolutions and other elements of planets, no hint is anywhere given as to how these were calculated and no information of the observations taken has been recorded in them. But they do not take into considaration the conditions in ancient times and the beliefs of our people. In those times when even scripts or any means of writing, not to speak of the printing presses, were not easily available or were even non-existent and all knowledge was preserved by the tradition of being vocally imparted by the teacher to his disciples. Hence, it was but natural that only the siddhāntas which embodied the results of research survived while their sources perished. Again, nobody will now feel astonished if one predicts the time of the occurrence of an eclipse. But in ancient times a man who could predict these phenomena was naturally considered to be superhuman. If he compiled a work, he would naturally incorporate in it only the resulting principles without mentioning their preliminary forms or the means employed in arriving at them. Then in course of time, the work would possibly come to be regarded as ‘apauruṣeya’ (divine) after the author’s name is forgotten & lost ;