Sidereal Astrology is the oldest form of astrology in the world which uses the actual positions of the stars in the sky. It has been widely used by the Persians, Vedics, and the Pre-Hellenic western world. In comparison, Tropical Astrology was created by Hellenic Greek philosophers as a way to base the astrological signs on the seasons. This involved adjusting the stars to match the Spring equinox with the beginning of the zodiac at 0 degrees Aries. Since the Earth's axis is slightly changing relative to the constellations, the Spring equinox now falls at 4 degrees Pisces. This is a variance of 26 degrees. For example, if your Sun sign was at 12 degrees Virgo in Tropical Astrology it would mean the Sun was actually at 16 degrees Leo when you were born. (Find out your sidereal signs here.)
The origin of Tropical Astrology comes from the Western dynasties. The teachings were passed down throughout the West while the rest of the world rejected these ideas. Later, during the Middle Ages in Europe, Kings became the heads of centralized nation states and the institutions within them. Thus, Tropical Astrology was popularized based on the approved teachings of the time. This model fixed the location of the stars as they were in the sky during approx. 285AD. A chart cast in this way would have us operating in a continuous loop in the Age of Aries collectively. Today, we are in the Age of Pisces moving into the Age of Aquarius and we need an astrological system that reflects this.
In the simplest terms, Tropical Astrology is disconnected from our natural state of being. While it does exist as a creation of the human mind within the collective psyche, it does not actually correspond with the natural world. Tropical Astrology requires extra math to calculate the adjusted locations of the celestial bodies. Sidereal Astrology, on the other hand, is simple and based on where the stars are in the sky. If you were to go outside and look for Venus, for example, Tropical Astrology might tell you she’s in Gemini when in fact she is in Taurus. In the past, the average person would have been none the wiser. Today, anyone can check the positions of the planets against the stars with their smartphone using an app called Star Chart. Sidereal Astrology can be as simple as going outside at night and looking up at the sky.