Bharatiya Jyotihshastra (History of Indian Astronomy), translated by R. V. Vaidya v1.c5.82

v1.c5.82

The attention of our people was drawn to the study of celestial bodies from very ancient times; still considerable time must necessarily elapse before any subject can evolve itself into a science. Similarly, a long time must have elapsed before the standard works on the subject of astronomy could be written, and it is obvious that the works which were written in the beginning of the evolution of the subject must have contained simple statements of facts of an elementary nature and those too of only broad outlines. The most ancient of the astronomical works extant in these days is the Vedāṅga Jyotiṣa. It deals with the mathematical aspect of only the sun and the moon; the Atharva Vedāṅga Jyotiṣa may be a latter work*. This deals with some aspects of the second and the third branches of astronomy.