Christopher Daly is a St. Paul-based Astrologer who has been practicing the Sidereal method since 2010. Since then he has worked with clients to provide insights into their personal, financial, and romantic lives while deepening his studies of Astrology’s relation to physiology, psychology, and spirituality. He uses an integrated approach to explore the questions unique to each client and uncover the unconscious patterns which impede personal and interpersonal growth.
A student of world philosophy with an interest in occult science and metaphysics, Christopher is committed to serving others through his work, understanding that our purpose on this plane of existence is to gather experiences, grow in self-knowledge, and consciously evolve as soul-beings. His Astrological practice facilitates this growth through examination of past and present lives and through the freedom that comes from greater understanding, acceptance, and forgiveness.
The Sidereal method:
What is the difference between the Tropical and Sidereal systems of Western astrology?
Back in 2010 there was a rather sensational headline featured on The Huffington Post that read “New Zodiac Sign Dates: Ophiucus the 13th Sign?” The article, written by their editor in charge of trends and social media, was read fairly widely and inspired many conversation between followers of pop astrology as well as skeptics.
As It turned out that the article was more about the Precession of the Equinoxes than it was about the discovery of a constellation, but it garnered enough attention (and consternation) to warrant multiple bottom-of-the-page amendments, including a follow-up by the featured Astronomer that this information was not “new” at all. So what was this all about?
What the article actually highlighted was the major difference between the Western Tropical system of astrology and the Sidereal system. The Tropical system is the one which is most familiar to readers of newspaper horoscopes in the US, and uses the same signs and constellations as the Western Sidereal system but different dates. The reason for the different dates is simple: Tropical astrologers render their calculations on the location of the sun at the solstices and equinoxes, dividing the sky evenly among the 12 signs between those dates. This does not, however, reflect the positions of the constellations to which those signs belong as seen we see them in the sky. The same is true for the background against which the heavenly bodies within our solar system appear to move from here on Earth: Tropical astrologers place the planets on the solstice/equinox dependent map rather than looking at their positions in the sky relative to the background of stars. The Sidereal system, on the other hand, bases its calculations on the strict, astronomical location of the planets and luminaries. The dates used in the Sidereal system are the same as those used in Vedic (Indian) astrology, and it has always been this way. But how did this schism occur?
As the link above explains, due to the subtle magnetism of the sun and moon the earth wobbles on its axis and creates the illusion that the constellations are slowly marching across the sky from year-to-year rather than remaining fixed in place. This is to say that one might reasonably assume that the Earth-relative position of Antares, the heart of the constellation Scorpio, will be the in the same spot in our sky on November 27th of one year as it is on November 27th of the next year, with the same being true of all other stars. While this may appear to be the case throughout an average lifetime, it is known that if one were to wait 72 years the position of Antares will have changed by exactly one degree relative to that Earth position. This means that not only do the planets move through the constellations, but that the constellations themselves move (though on a much longer timeline). This timeline lasts exactly 25,772 years.
So when was the last time that the Sun rose at 0 degrees Sidereal Aries on March 21st (the same as Tropical Aries)? Some time around 400 A.D. and the fall of the Roman empire. Since then the stars have precessed 25 degrees and the beginning of Sidereal Aries has shifted to April 18th. In effect, there is very little overlap today (roughly 5 degrees) between the Tropical signs and the constellations they take their namesakes from, with some missing the mark completely. What does this mean for someone born as a Taurus in tropical system? Unless you were born in that sweet spot (between May 13th and 20th) the sun was actually in Aries…for those Tropical Geminis born May 21st-June20th, well, the sun was actually in Taurus!
From the above you may take one more important feature of the Sidereal zodiac: it does not arbitrarily divide the sky into symmetrical units. Siderealists observe the location of the planets and stars as astronomers do, taking astrological practice out of the realm of abstraction and placing it firmly within the material world.
Mars' Garden Astrology 