''
Sidereal'' and ''
tropical
The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in
the Southern Hemisphere at S. The tropics are also referred to ...
'' are terms used to describe two different definitions of a year, applied in
sidereal solar calendar
A solar calendar is a calendar whose dates indicate the season or almost equivalently the apparent position of the Sun relative to the stars. The Gregorian calendar, widely accepted as a standard in the world, is an example of a solar calendar.
...
s or
tropical solar calendars. In astrology, they refer to two different systems of
ecliptic coordinates
The ecliptic coordinate system is a celestial coordinate system commonly used for representing the apparent positions, orbits, and pole orientations of Solar System objects. Because most planets (except Mercury) and many small Solar System bodi ...
used to divide the
ecliptic
The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic again ...
into twelve "signs". Each sign is divided into 30 degrees, making a total of 360 degrees.
While sidereal systems of astrology define the signs relative to the apparent backwards movement of
fixed star
In astronomy, fixed stars ( la, stellae fixae) is a term to name the full set of glowing points, astronomical objects actually and mainly stars, that appear not to move relative to one another against the darkness of the night sky in the backg ...
s of about 1 degree every 72 years from the perspective of the Earth, tropical systems define 0 degrees of
Aries
Aries may refer to:
*Aries (astrology), an astrological sign
*Aries (constellation), a constellation of stars in the zodiac
Arts, entertainment and media
* ''Aries'' (album), by Luis Miguel, 1993
* ''Aries'' (EP), by Alice Chater, 2020
* "Aries" ...
to coincide with the
vernal point
A solar equinox is a moment in time when the Sun crosses the Earth's equator, which is to say, appears directly above the equator, rather than north or south of the equator. On the day of the equinox, the Sun appears to rise "due east" and set ...
or vernal equinox (also known as the March equinox in the Northern hemisphere), and define the rest of the zodiac from this point.
Sidereal astrology maintains the alignment between signs and
constellations
A constellation is an area on the celestial sphere in which a group of visible stars forms a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object.
The origins of the earliest constellation ...
via corrective systems known as
ayanamsas (Sanskrit: ''
'ayana'
'' "movement" + ''
'aṃśa "component"), to allow for the observed
precession of equinoxes
In astronomy, axial precession is a gravity-induced, slow, and continuous change in the orientation of an astronomical body's rotational axis. In the absence of precession, the astronomical body's orbit would show axial parallelism. In partic ...
, whereas tropical astrology is based upon the seasonal cycle of the Northern Hemisphere.
This has caused the two systems, which were aligned around 2,000 years ago, to drift apart over the centuries.
Ayanamsa systems used in Hindu astrology (also known as
Vedic
upright=1.2, The Vedas are ancient Sanskrit texts of Hinduism. Above: A page from the '' Atharvaveda''.
The Vedas (, , ) are a large body of religious texts originating in ancient India. Composed in Vedic Sanskrit, the texts constitute the ...
astrology) include the Lahiri ayanamsa and the Raman ayanamsa.
The
Fagan-Bradley ayanamsa is an example of an ayanamsa system used in Western sidereal astrology.
As of 2020,
sun signs calculated using the
Sri Yukteswar
Sri Yukteswar Giri (also written Sriyuktesvara, Sri Yukteshwar) (Devanagari: ) (10 May 1855 – 9 March 1936) is the monastic name of Priya Nath Karar (also spelled as Priya Nath Karada and Preonath Karar), an Indian monk and yogi, and the g ...
ayanamsa were around 23 degrees behind tropical sun signs.
Per these calculations, persons born between March 12 - April 12, for instance, would have the sun sign of
Pisces
Pisces may refer to:
* Pisces, an obsolete (because of land vertebrates) taxonomic superclass including all fish
* Pisces (astrology), an astrological sign
* Pisces (constellation), a constellation
**Pisces Overdensity, an overdensity of stars in ...
.
By contrast, persons born between March 21 - April 19 would have the sun sign of Aries per tropical calculations.
Cyril Fagan
Cyril Fagan (born Dublin, Ireland, May 22, 1896, died Tucson, Arizona, United States, January 5, 1970) was an Irish astrologer,
Generally considered ''the father'' - alongside Donald A. Bradley, ''the mother'', of Sidereal astrology
'' Sid ...
, a Western sidereal astrologer, assumed the origin of the zodiac to be based on a major conjunction that occurred in 786 BC when the vernal equinox lay somewhere in mid-Aries
http://www.solsticepoint.com
/ref> corresponding to a difference of some 39 degrees or days.
Astronomic zodiac
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.
For the purpose of determining the constellations in contact with the ecliptic, the constellation boundaries as defined by the International Astronomical Union
The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...
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, as the first sign rather than of Aries. The IAU defined the constellation boundaries without consideration of astrological purposes.
The dates the Sun passes through the 12 astronomical constellations of the ecliptic
The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic again ...
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
The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in
the Southern Hemisphere at S. The tropics are also referred to ...
and sidereal dates are given as well.
See also
* Great year
* Astrology and science
Astrology consists of a number of belief systems that hold that there is a relationship between astronomical phenomena and events or descriptions of personality in the human world. Astrology has been rejected by the scientific community as havin ...
* Synoptical astrology
References
* "The Real Constellations of the Zodiac." Dr. Lee T. Shapiro, ''Planetarian,'' Vol 6, #1, Spring (1977)
*"The Real, Real Constellations of the Zodiac." John Mosley, ''Planetarian,'' Vol. 28, # 4, December (1999
* "The Primer of Sidereal Astrology," Cyril Fagin and Brigadier R. C. Firebrace, American Federation of Astrologers, Inc., (1971)
* A History of Western Astrology, by S. Jim Tester, 1987, republished by Boydell Press (January 1999),,
*
External links
Vedic astrology -- critically examined
by Dieter Koch
Dieter or dieter may refer to:
* A person committed to dieting
People
Dieter is a German given name (), a short form of Dietrich, from ''theod+ric'' "people ruler", see Theodoric.
Given name
*Dieter Althaus (born 1958), German politician
* ...
, with an extended discussion of sidereal and tropical astrology.
{{DEFAULTSORT:Sidereal Astrology
Astrology by type
Hindu astrology
History of astrology