as to dictionary; we find that
1 Astronomy, esp. in its practical aspects, as the measurement of time, prediction of natural phenomena, etc. Also more fully natural astrology.
2 The supposed art of foretelling or counseling in human affairs by interpretation of the motions of celestial objects. Also more fully judicial astrology.
So to say, practical utility of properties found in astro bodies and their impacts to our nature & beings are considered in this branch of Science ASTROLOGY.
astrology is also follows with a system of logic that an instance of the application of science or investigation.