Distinguishing characteristics

* The primary goal of astronomy is to understand the physics of the universe. Astrologers use astronomical calculations for the positions of celestial bodies along the ecliptic and attempt to correlate celestial events (astrological aspects, sign positions) with earthly events and human affairs. Astronomers consistently use the scientific method, naturalistic presuppositions and abstract mathematical reasoning to investigate or explain phenomena in the universe. Astrologers use mystical/religious reasoning as well as traditional folklore, symbolism and superstition blended with mathematical predictions to explain phenomena in the universe. The scientific method is not consistently used by astrologers.

* Astrologers practice their discipline geocentricically [12] and they consider the universe to be harmonious, changeless and static, while astronomers believe that the universe is without a center and is dynamic, expanding outward. [13]

* Astrologers are deterministic; that is, they believe that everything in the universe is orderly, predictable and predetermined, that nothing happens at random.[14] Astronomers, on the contrary, believe that both order and randomness simultaneously exist in the universe; that is, astronomers believe the universe is not entirely orderly, predictable and predetermined, that randomness does in fact exist in the universe to at least some extent. Random cosmic collisions and other random phenomena occur everywhere in the universe.

* Both astrologers and astronomers see Earth as being an integral part of the universe, that Earth and the universe are interconnected as one cosmos (not as being separate and distinct from each other). However, astrologers philosophically and mystically portray the cosmos as having a supernatural, metaphysical and divine essence that actively influences world events and the personal lives of people.[15]. However, astronomers teach that nothing in the universe is divine or supernatural, and that nothing in outer space directly manipulates world events or the personal lives of people in supernatural or divine ways. Astronomers believe that, because the Earth is an integral part of the universe, celestial objects are just as humbly natural as terrestrial objects, being composed of exactly the same substances, and controlled by exactly the same forces, as objects on Earth. The substances iron, hydrogen, sulfur, carbon, nitrogen and oxygen, as well as the fundamental interactions of gravity, electromagnetism, weak force and strong force, are just as prevalent within the stars and planets as they are on Earth.

* Astronomers refers to star patterns as "constellations" and "asterisms", while astrologers refer to star patterns as "signs". Contemporary astronomers, who are academic instead of mystical or superstitious, have little use for the constellations, accepting them only as "regions" or "provinces" of the sky for scientific observation and academic study, instead of as real pictures in the sky. Unlike the mystical and superstitious astrologers, who believe and teach that pictures truly exist among the constellations and have supernatural or divine influences on people, today’s academic mainstream astronomers believe and teach that pictures do not truly exist among the constellations. Instead, today’s academic mainstream astronomers believe and teach that people and cultures throughout history only imagined pictures among the constellations and composed myths and stories about what they imagined in the sky, and that such mere "pictures of the imagination" have no supernatural or divine influences on people whatsoever. Today’s academic mainstream astronomers believe and teach that a constellation is nothing more than a group of stars in a specific region of the sky, and that any person or culture, at any time or place, can imagine whatever picture they wish among a particular group of stars, as history proves via the many ancient and modern cultures, each culture having its own unique star lore.

* Astrologers and astronomers differ in their approach to concepts such as constellations. Astronomers recognize a thirteenth constellation, Ophiuchus, in addition to the twelve astrologers recognize. Astrologers traditionally omit Ophiuchus from their zodiacal signs, preferring twelve due to a long-standing conceptual system in which twelve signs are vital. In addition, due to the 26,000 year precession cycle of Earth on its axis of rotation, the constellations along the ecliptic are no longer positioned the same as they were during Aristotle and Ptolemy's day (when the current astrological system was first established). The Sun, for example, no longer enters Aries on the vernal equinox, instead, it now enters Pisces during that time, making Pisces the true contemporary first sign of the zodiac instead of Aries. Precession only affects the astrological traditions employing the tropical zodiac, such as Western astrology, however. Indian astrology, which uses the sidereal zodiac, uses modern star positions.