Sidereal astrology
From Freepedia
Sidereal astrology is the practice by some western and all Indian astrologers of basing their study of the sky on the actual position of the planets in relation to the starry background. Most western astrologers adopt the tropical zodiac approach which defines the zodiac as beginning at the vernal equinox, thus linking their astrological meanings to seasonal changes rather than the background of stars in the sky.
Sidereal astrologers claim their approach is more in keeping with the ancient traditions of the subject. Until the middle ages all astrology was conducted using the sidereal approach. They claim it was ignorance on the part of mediaeval astrologers concerning precession of the equinoxes that led tropical astrologers into the erroneous tropical zodiac.
All astronomers as well as tropical and sidereal astrologers still base their measurement of the sky on a zero point taken as the position of the vernal equinox on the ecliptic. This has the same significance in the sky as the prime meridian on the Earth’s globe, it is the zero point of a 360 degree arc which is used to give a location for an object in the sky. Sidereal astrologers then add a correction to this point to allow for the precession of the equinoxes. They do this so that the zodiacal signs used in their astrology coincide with the constellations of stars to which they refer. This correction is called the ayanamsa and different values are used by different sidereal astrologers. This value is usually around 24 degrees at the present time and is constantly increasing as the equinoxes precess.
About 2,000 years ago, the two zodiacs were in approximate agreement and the vernal equinox fell at the start of the constellation Aries.
Nearly all astrologers, tropical and sidereal, agree that the ecliptic should be divided into twelve equal segments to form the zodiac, they differ on where the zodiac begins. Astronomers have very precise boundaries between constellations agreed at an international convention in 1936 but astrologers see these as arbitrary and not having a bearing on astrology.
A small number of astrologers wish to include other constellations, such as Ophiuchus, in their zodiac and use thirteen signs instead of twelve. For example, the tropical zodiacal system neglects the constellation of Ophiuchus, which was recognised as a constellation of the sidereal zodiac at least 1,700 years ago.
See also
- Tropical zodiac (for table of dates)
- Astrology
- Zodiac
- sidereal time
