When St. Augustine calls Atlas magnus astrologus he goes back to the euhemeristic doctrine that turns heroes into sages (De Civitate Dei XVIII, 39; cfr. Plinius Nat.Hist. II, 31; VII, 203; Vitruvius VI, 10, 6; Diodorus S. III, 60, 2; IV, 27, 17). And not only Atlas: Uranus, Belo, Thoth, Prometeus, Atraeus, Chiro the Centaur also disclosed astrology to man (cfr. Jo. Chr. Heilbronner, Historia Matheseos universae a mundo condito ad saeculum post Chr. n. XVI, Lipsiae 1742, pagg. 54ff.). St. Augustine tells us that Atlas lived in the same period as Moses, who was, according to a Philo, a mathematician, an astronomer, a geometer, a musician and an excellent philosopher and he learned the science of the sky from the Assyrians (vita Mosis I, 23). Before Moses, Abraham taught mathematics and astronomy to the Egyptians, who did not know anything about it (Berossos ap. Josephus, ant. jud. I, 8, 2; cfr. Eusebius, praep. ev. IX, 16). Those men had received the science of the sky through a revelation.
Moreover, there is a tradition according which both astrology and astronomy are taught by rebel angels (cfr. Book of Enoch VIII, 4), but the Greeks believed that those two sciences had been revealed by gods to "the kings loved by divinity" (Lucianus de astr. 1; cfr. Achilles Tatius isag. 1), namely per divine gift, munere caelestum, as Manilio says (I, 26).