(1) All ancient astrologers placed the greatest significance upon heliacal risings and settings and ancient Mesopotamian astrology was also heavily predisposed to observance of this kind of planetary phenomena.(2) The Greeks and Romans, with fairly useless calendars, continued to depend upon observing the heliacal risings and settings of stars.(3) It is possible that all the planetary orbs originate from an early attempt to record heliacal obscurity.
