Today there are two existing schools of astrology. The first one is based on the tropical zodiac and the second uses the sidereal zodiac, which is very closely linked to the constellations.
Most astrologers prefer to refer to the tropical zodiac, which is calculated according to the solar cycle beginning on 21 March, when the Sun enters the sign of Aries. This marks the beginning of spring. This kind of astrology is also known as seasonal, even though in the southern hemisphere, 21 March marks the beginning of autumn. This is the one used by the astrologers of Free Horoscope.
The calculations of Sidereal Astrology are based on the fixed stars, which are commonly known as the constellations. Astrologers in ancient times used this method of calculation and Hindus still use it today. The constellations had been defined in ancient times in terms of 30° segments. This zodiac is quite distinct from the tropical zodiac and shows a discrepancy of 24°00΄004, with 1 January as the date of reference. This is known as Ayanamsa. A person born when the Sun's position is before 24° within a particular sign is considered to be born under the previous one, rather than using the Sun's actual position. This discrepancy increases by one degree every 72 years. To check this out, you simply need to draw up the birth chart of a person born before 1900 and you'll be able to see that the discrepancy was lower then.
Sidereal Astrology
In calculating your birth sign, the constellation of the solar system actually illuminated by the Sun at the time of birth is taken into consideration. For a person born under the sign of Aries, the Sun is in the constellation of Aries as seen from the Earth. With the time and geographical situation, we can calculate the exact position of the Sun in relation to the constellation.
To find out the exact position of the planets, you need to look at the ephemeris. You then need to subtract the number of degrees indicated in the ephemeris for each planet, the Ascendant and the Houses, otherwise known as Ayanamsa. At the moment, Ayanamsa is 24°. This is not a fixed value, as it is always changing and continually increasing.
These 24 degrees are spread over approximately 24 days in discrepancy with the calendar of the astrological signs. To enable us to go further into our analysis of sidereal astrology, we are going on to define its most important terms.
Ayanamsa is a Sanskrit word, from Ayana, meaning movement, and Amsa, meaning degree. This term gained importance under Ptolemy in the second century A.D. It was Ptolemy who persuaded astrologers to use the vernal point of the spring equinox as a basis for calculating the position of the planets. Hindus, however, have always refuted Ptolemy's method and call this discrepancy Ayanamsa. Ayanamsa is not fixed, but increases by one degree each century. Tropical astrology does not accept this theory. This movement does not make astrology an exact science and it is this idea of uncertainty that the Hindus find disturbing, for example.
The vernal point is an imaginary point. This is the point where the Sun's rays are distributed equally over the northern and southern hemispheres. It serves as a reference point for calculating the angle formed by the planets of the solar system to the Sun and the Earth. The vernal point of the spring equinox is constantly moving and takes around 2000 years to travel across each sign. This leads to each era bearing the name of the relevant sign. At the moment, for example, we are in the Age of Pisces and in around a hundred years we will reach the Age of Aquarius.
The movement of the vernal point of the spring equinox is related to the fact that the Earth follows an elliptical path around the Sun. The plane of the ecliptic represents the axis on which all the planets are aligned in orbit, with the exception of Pluto. The Sun is at the centre of the system and everything around it is in the plane of the ecliptic. The constellations in the cosmic universe form the zodiac. Each constellation emits vibrations which have an influence on our planet and our behaviour. The universe is magnetic.
The Tropical Zodiac
This form of astrology is based on a different foundation from sidereal astrology. Tropical astrology includes an annual cycle and takes its four cardinal points, the two solstices and two equinoxes, into consideration in defining the zodiac. The spring equinox corresponds to the sign of Aries, which is at 0° (this is called the vernal point). The zodiac is then divided into segments of 30° and each of these segments corresponds to an astrological sign. The names of these signs are the same as in sidereal astrology. However, these two forms of astrology do not coincide. The movement of the polar axes of the Earth is very slow, rather like a spinning top. This movement of precession corresponds to the rotation of the Earth's axis and is not always in the same position with regard to the stars. The tropical zodiac is 24° ahead of sidereal astrology and the tropical zodiac is seen as seasonal.
The beginning and end of a cycle are based on the winter solstice, the moment when the Sun's light is at its lowest level. The middle of the cycle corresponds to the summer solstice, the moment when the Sun's light is at its highest level. The middle point of the Sun's ascension in the sky corresponds to the spring equinox and the middle of its descent to the autumn equinox.
The winter solstice is in the sign of Capricorn, the spring equinox in Aries, the summer solstice in Cancer and the autumn equinox in Libra. These are the four cardinal signs (south, east, north and west). Space and time are therefore intrinsically linked in the tropical zodiac. Capricorn is the symbol of maximal contraction and the sign that heralds things coming to an end. This is the lowest point in the annual cycle. Aries on the other hand signifies vital enthusiasm, renewal and birth. Cancer is synonymous with receptiveness and the ability to listen, being at peace and receptive to others. Summer is the period of harvesting and gathering. Finally, Libra symbolises decline, reconsideration and restructuring before the darkness arrives. This is the sign of the setting sun. Autumn is a transitory season, a turning-point, looking towards completion, a respite before rebirth.
The main criticism that can be levelled at the tropical zodiac is its focus solely on the northern hemisphere. Movement and the seasons are reversed in the southern hemisphere. For the zodiac to work as a cohesive whole, this might suppose the need to turn all data upside-down if you live in the southern hemisphere.
Links between the tropical zodiac and sidereal astrology
Astrology's detractors often question this discrepancy between the two zodiacs. For them, an exact science should only involve one path to knowledge, which should be fixed and not malleable. In response to these detractors, it is first of all important to remember that Astrology is derived from different traditions and that interpretation methods change depending on the culture. It is possible to describe an individual's personality using different methods. The differing forms of astrology complement each other and never contradict each other.
Both zodiacs, sidereal and tropical, are valid and offer two potential ways of interpreting the universe. The first zodiac is based on the Sun, while the tropical zodiac is based on the Moon. A comparison of both zodiacs can help us understand an individual from different angles. Both points of view complement each other and it is easy to find a number of similarities between both these forms of astrology. These two forms of sacred science do not oppose each other in any way, but actually complement each other.
As a general rule, it is the seasonal zodiac that is used most by western astrologers. This is probably because it is very closely linked with nature and appeals to the senses and receptivity. The sidereal zodiac is better adapted to spirituality, being less tangible and more rational. However, the questions asked of astrologers are very often down-to-earth, relating to professional life, health, love-life, etc. In these cases, it quickly becomes evident that the sidereal zodiac is very suited to this type of question. It responds to human issues without difficulty and is in tune with human concerns. 90% of western astrologers use the tropical zodiac.
Whichever zodiac is used, it is always based on the same astrological signs, twelve in total. No scientist has ever been able to say whether one form of astrology is better than the other. Astrology is a sacred science and only valid in relation to the message it carries. It cannot be classified among the so-called rational sciences, such as physics or mathematics. Astrology is designed to guide the individual through life, through moments of doubt, when he or she is happy to call on an astrologer to learn which path to follow, and above all, how to react in the face of difficult situations? The enlightenment provided by astrology of an individual's life brings tranquillity, whichever form of astrology is used.