Astronomical Definitions:

Whether in western astrology or Indian astrology, the signs are named after the constellations that were closest to the time of the choice of these names, there are nearly 3000 years, but the correspondence between names and signs names of constellations no longer exists today because of the precession of the equinoxes . In contrast, Chinese astrology, there has never been a link between the names of the signs and constellations. The modern calendar is defined by the movement of the Earth around the Sun (calendar-type "solar"), and the orbit of the Earth being substantially circular, it is easy to determine what sign goes the sun on a given day: his position is virtually identical from one year to another, if we neglect the slight variation due to leap years. These are the dates in the articles dealing with different signs. Sidereal astrology, unlike classical astrology, to benchmark against the constellations and stars. For this form of astrology, it is necessary to take into account the effect of the precession of the equinoxes , which derives the vernal point of a degree every 72 years (and therefore, significantly shifts the timing related to the stars of one day every 72 years). This incremental change leads to a cycle of 26,000 years, after which the constellations return to their original position (the movement of the stars near). To determine where the sign is the Moon or a planet, it is necessary to use an almanac , or a specialized computer program in astronomy . Such programs can quickly calculate a horoscope , which allows the astrologer to focus on the astrological interpretation rather than calculation. According to the historian of astrology Jacques Halbronn , cutting at 12 is separated soli-lunar calendar as the start of the zodiac is the sign or the constellation of Aries. He said the theory was enough to cut all aspects astrological cycle, using conjunctions occur between a planet and a fixed star (especially the 4 stars say royal), which posed no problem in terms of precession of the equinoxes since it in no way dependent on the season.