Tropical Astrology is the old astrological division of the sky. When the Zodiac was invented, the position of the constellations were written down. But since then, the whole Zodiac has shifted almost a whole sign due to the Precession, so whoever was once born a Virgo, is now probably born a Leo - with the personality changes that come with it. Tropical Astrology ignores this, and keeps using the old tables - which have nothing to do with where the planets actually are in the sky.
Sidereal Astrology acknowledges the problem with the shifting signs, but digs itself deeper into the ludicrous: The more sidereal astrologers try to follow the real division of the sky, the more they are distancing themselves from the old wisdom. Sidereal astrologers cannot claim to build on ancient knowledge, but have to change the signs and characteristics over time. They are in turn making the whole concept of Astrology invalid. The real astronomical signs are a few days off from the Sidereal system by now - so not even Sidereal Astrology is using the correct star signs.
Sidereal astrology uses the actual constellation in which the sun is located at the moment of birth as its basis; tropical astrology uses a 30-degree sector of the zodiac as its basis.
Tropical astrology is the most popular form and it assigns its readings based on the time of the year, while generally ignoring the positions of the sun and constellations relative to each other. Sidereal astrology is used by a minority of astrologers and bases its readings on the constellations near the sun at the time of birth.
According to some astrologers, the data support the hypothesis that there is a connection between heavenly bodies and human events. There are correlations too synchronous to be mere chance between astrological signs and such things as personality, emotions and human destiny.
and [[tropical year|tropical]]
are astronomical terms used to describe two different definitions of a "year". They are also used as terms for two systems of Ecliptic coordinate system
used in astrology
Both divide the ecliptic
into a number of "signs" named after constellation
, but while the sidereal system defines the signs based on the fixed star
, the tropical system defines it based on the position of vernal equinox
(i.e., the intersection of the ecliptic with the celestial equator
. Because of the precession of the equinoxes
the two systems do not remain fixed relative to each other but drift apart by about 1.4 arc degrees per century.
The tropical system was adopted during the Hellenistic period and remains prevalent in Western astrology
A sidereal system is used in Hindu astrology
and in some 20th century systems of Western astrology
While classical tropical astrology is based on the orientation of the Earth relative to the Sun and planets of the solar system
sidereal astrology deals with the position of the Earth relative to both of these as well as the stars of the celestial sphere
The actual positions of certain fixed stars
as well as their constellations is an additional consideration in the horoscope.
File Equinox positions.png
The red line is a section of the apparent path traced by the Sun through the Earths year. The red/green line is a projection of the Earths equator onto the celestial sphere. The crossing point of these two lines is the spring equinox. In 1500 BCE it was near the end of the constellation of Aries, in 500 BCE it was near the beginning of the constellation of Aries, and in 150 CE (the time of Ptolemy) it was in the center of the constellation of Pisces.]]
The classical zodiac
was introduced in the neo-Babylonian
period (around the seventh to the sixth century BCE). At the time, the precession of the equinoxes
had not been discovered. Classical Hellenistic astrology
consequently developed without consideration of the effects of precession.
The discovery of the precession and most of the objects in space, of the equinoxes, is attributed to Hipparchus
a Greek astronomer active in the later Hellenistic period (ca. 130 BCE).
writing some 250 years after Hipparchus, was thus aware of the effects of precession. He opted for a definition of the zodiac based on the point of the vernal equinox
i.e., the tropical system.
While Ptolemy noted that Ophiuchus is in contact with the ecliptic, he was aware that the 12 signs were just conventional names for 30-degree segments.
The Hindu Jyotisha system opted for defining the zodiac based on the fixed stars, i.e., directly tied to the eponymous zodiacal constellations, unlike Western astrological systems.
Traditional Hindu astrology
is based on the sidereal or sidereal zodiac
accounting for the shift of the equinoxes by a correction called ayanamsa
The difference between the Vedic and the Western zodiacs is currently around 24 degrees. This corresponds to a separation of about 1,700 years, when the vernal equinox was approximately at the center of the constellation Pisces (astrology)
and the tropical and sidereal zodiacs coincided (around AD 290, or at 23.86° as of 2000. The separation is believed to have taken place in the centuries following Ptolemy
(second century AD), apparently going back to Indo-Greek
transmission of the system. But earlier Greek astronomers like Eudoxus spoke of a vernal equinox at 15° in Aries, while later Greeks spoke of a vernal equinox at 8° and then 0° in Aries (cf. p. 16, S. Jim Tester in ref.), which suggests the use of a sidereal zodiac in Greece before Ptolemy and Hipparchus.
Sidereal western astrology
Some western astrologists have shown interest in the sidereal system during the 20th century.
assumes the origin of the zodiac in 786 BC, when the vernal equinox lay somewhere in mid-Aries, based on a major conjunction that occurred that year,
corresponding to a difference of some 39 degrees or days.
Most sidereal astrologers simply divide the ecliptic into 12 equal signs of 30 degrees but approximately aligned to the 12 zodiac constellations. Assuming an origin of the system in 786 BC, this results in a system identical to that of the classical tropical zodiac
shifted by 25.5 days, i.e., if in tropical astrology Aries is taken to begin at March 21, sidereal Aries will begin on April 15.
A small number of sidereal astrologers do not take the astrological signs as an equal division of the ecliptic, but define their signs based on the actual width of the individual constellations. They also include constellations that are disregarded by the traditional zodiac, but are still in contact with the ecliptic.
Stephen Schmidt in 1970 introduced Astrology 14,
lt;s>, a system with additional signs based on the constellations of Ophiuchus
In 1995, Walter Berg
introduced his 13-sign zodiac
which has the additional Ophiuchus (astrology)
Bergs system was well received in Japan
after having his book translated by radio host Mizui Kumi ( ja 水井久美
For the purpose of determining the constellations in contact with the ecliptic, the constellation boundaries as defined by the International Astronomical Union
in 1930 are used. For example, the Sun enters the IAU boundary
of Aries on April 19 at the lower right corner, a position that is still rather closer to the "body" of Pisces than of Aries. Needless to say, the IAU defined the constellation boundaries without consideration of astrological purposes.
The dates the Sun passes through the 13 astronomical constellations of the ecliptic
are listed below, accurate to the year 2011. The dates will progress by an increment of one day every 70.5 years. The corresponding Tropical astrology
and sidereal dates are given as well.
| aligncenter cellpadding5 border1 rulesall
! colspan2 | Constellation
|| Sidereal DateCyril Fagan
| Tropical date || IAU DefinitionWalter Berg
lt;ref>http://articles.latimes.com/2011/jan/14/news/la-sciw-astrological-signs-20110114/2 New astrological sign: Professor finds horoscopes may be a little off kilter] a
January 14, 2011 article from the [[Los Angeles Times]]
| Image Aries.svg
|| Aries (astrology)
|| April 15–
May 15 || March 21–
April 20 || April 18–
| Image Taurus.svg
|| Taurus (astrology)
|| May 16–
June 15 || April 21–
May 20 || May 13–
| Image Gemini.svg
|| Gemini (astrology)
|| June 16–
July 15 || May 21–
June 20 || June 21–
| Image Cancer.svg
|| Cancer (astrology)
|| July 16–
August 15 || June 21–
July 21 || July 20–
| Image Leo.svg
|| Leo (astrology)
|| August 16–
September 15 || July 23–
August 24 || August 10–
| Image Virgo.svg
|| Virgo (astrology)
|| September 16–
October 15 || August 25–
September 22 || September 16–
| Image Libra.svg
|| Libra (astrology)
|| October 16–
November 15 || September 23–
October 22 || October 30–
| Image Scorpio.svg
|| Scorpio (astrology)
|| November 16–
December 15 || October 23–
November 21 || November 23–
| Image Ophiuchus zodiac.svg
|| Ophiuchus (astrology)
|| colspan"2"|N/A || November 29–
| Image Sagittarius.svg
|| Sagittarius (astrology)
|| December 16–
January 14 || November 22–
December 21 || December 17–
| Image Capricorn.svg
|| Capricorn (astrology)
|| January 15–
February 14 || December 22–
January 20 || January 20–
| Image Aquarius.svg
|| Aquarius (astrology)
|| February 15–
March 14 || January 21–
February 19 || February 16–
| Image Pisces.svg
|| Pisces (astrology)
|| March 15–
April 14 || February 19–
March 20 || March 11–
* Great year
* Astrology and Science
* "The Real Constellations of the Zodiac."
lt;s>.. Dr. Lee T. Shapiro, Planetarian,
lt;s>, Vol 6, #1, Spring (1977). http://www.ips-planetarium.org/planetarian/articles/realconstellations_zodiac.html]
*"The Real, Real Constellations of the Zodiac."
lt;s>. John Mosley, Planetarian,
lt;s>, Vol. 28, # 4, December (1999).http://www.ips-planetarium.org/planetarian/articles/realrealconstellations.html]
* "The Primer of Sidereal Astrology,"
lt;s>, Cyril Fagin and Brigadier R. C. Firebrace, American Federation of Astrologers, Inc., (1971) ISBN 0-86690-427-1
* A History of Western Astrology, by S. Jim Tester,1987, republished by Boydell Press (January 1999),ISBN 0-85115-255-4, ISBN 978-0-85115-255-4
*http://www.astro.com/astrology/in_vedic2_e.htm Vedic astrology -- critically examined] by Dieter Koch, with an extended discussion of sidereal and tropical astrology.
Category Astrology by type
Category Hindu astrology
Category History of astrology