The mainstream model of astrology most of us use is tropical geocentric. The tropical zodiac is the 12 zodiac signs we all use and are familiar with, and the 12 houses split or divided perfectly by 30 degrees. 12 houses x 30 degrees = 360 degrees. This is unchanging; was, is, and always will be since over 2,000 years ago.
But we don’t live in an unchanging world. At some point in time, astronomers discovered the precession of the equinox. Initially, they had no idea the earth wobbles continuously around its axis in 25,800-year cycle that’s caused by the Moon’s gravitational pull on the bulge at the earth’s equator.
The vernal equinox or the first day of spring in the Northern Hemisphere was marked by the zero point of the zodiac or the first degree of Aries; so as astronomers are looking out into the Heavens, the spring starts when the ecliptic, which is the path of the sun, intersects with the celestial equator.
Over the past almost three millennia, the intersection point shifted almost 36 degrees because of the wobble or precession, and this changes everything in terms of the dates of astrological signs. This is also why mainstream had almost no choice, but to “in a playful way” introduce Ophiuchus, the 13 zodiac sign back in 2010 or 2011.
The truth is that there is 13 signs, and your natal sun is most definitely in a sign that you’re not taking credit for.
SIDEREAL-that’s the zodiac that takes precession into account, and don’t worry about your birth chart because most websites that offer birth chart’s will give you the option of choosing tropical or sidereal (or Draconic, but that’s another story).
Capricorn January 20 – February 16
Aquarius February 16 – March 11
Pisces March 11 – April 18
Aries April 18 – May 13
Taurus May 13 – June 21
Gemini June 21 – July 20
Cancer July 20 – August 10
Leo August 10 – September 16
Virgo September 16 – October 30
Libra October 30 – November 23
Scorpius November 23 – November 29
Ophiuchus November 29 – December 17
Sagittarius December 17 – January 20