Zodiac

Zodiac

Overview

In astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

, the zodiac (Greek: ζῳδιακός, zōdiakos) is a circle of twelve 30° divisions of celestial longitude which are centred upon the ecliptic
Ecliptic
The ecliptic is the plane of the earth's orbit around the sun. In more accurate terms, it is the intersection of the celestial sphere with the ecliptic plane, which is the geometric plane containing the mean orbit of the Earth around the Sun...

: the apparent path of the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

 across the celestial sphere
Celestial sphere
In astronomy and navigation, the celestial sphere is an imaginary sphere of arbitrarily large radius, concentric with the Earth and rotating upon the same axis. All objects in the sky can be thought of as projected upon the celestial sphere. Projected upward from Earth's equator and poles are the...

 over the course of the year. The paths of the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

 and visible planet
Planet
A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...

s also remain close to the ecliptic, within the belt of the zodiac which extends 8-9° north or south of the ecliptic, as measured in celestial latitude.
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In astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

, the zodiac (Greek: ζῳδιακός, zōdiakos) is a circle of twelve 30° divisions of celestial longitude which are centred upon the ecliptic
Ecliptic
The ecliptic is the plane of the earth's orbit around the sun. In more accurate terms, it is the intersection of the celestial sphere with the ecliptic plane, which is the geometric plane containing the mean orbit of the Earth around the Sun...

: the apparent path of the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

 across the celestial sphere
Celestial sphere
In astronomy and navigation, the celestial sphere is an imaginary sphere of arbitrarily large radius, concentric with the Earth and rotating upon the same axis. All objects in the sky can be thought of as projected upon the celestial sphere. Projected upward from Earth's equator and poles are the...

 over the course of the year. The paths of the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

 and visible planet
Planet
A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...

s also remain close to the ecliptic, within the belt of the zodiac which extends 8-9° north or south of the ecliptic, as measured in celestial latitude. Historically, these twelve divisions are called signs
Astrological sign
Astrological signs represent twelve equal segments or divisions of the zodiac. According to astrology, celestial phenomena reflect or govern human activity on the principle of "as above, so below", so that the twelve signs are held to represent twelve basic personality types or characteristic modes...

. Essentially, the zodiac is a celestial coordinate system
Celestial coordinate system
In astronomy, a celestial coordinate system is a coordinate system for mapping positions on the celestial sphere.There are different celestial coordinate systems each using a system of spherical coordinates projected on the celestial sphere, in analogy to the geographic coordinate system used on...

, or more specifically an ecliptic coordinate system
Ecliptic coordinate system
The ecliptic coordinate system is a celestial coordinate system that uses the ecliptic for its fundamental plane. The ecliptic is the path that the sun appears to follow across the celestial sphere over the course of a year. It is also the intersection of the Earth's orbital plane and the celestial...

, which takes the ecliptic as the origin of latitude, and the position of the sun at vernal equinox as the origin of longitude.

Usage


It is known to have been in use by the Roman era, based on concepts inherited by Hellenistic astronomy from Babylonian astronomy of the Chaldean period (mid-1st millennium BC), which, in turn, derived from an earlier system of lists of stars along the ecliptic. The construction of the zodiac is described in Ptolemy
Ptolemy
Claudius Ptolemy , was a Roman citizen of Egypt who wrote in Greek. He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in Egypt under Roman rule, and is believed to have been born in the town of Ptolemais Hermiou in the...

's Almagest (2nd century AD).

The term zodiac derives from Latin zōdiacus, which in its turn comes from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

  (zōdiakos kuklos), meaning "circle of animals", derived from (zōdion), the diminutive of (zōon) "animal". The name is motivated by the fact that half of the signs of the classical Greek zodiac are represented as animals (besides two mythological hybrids).

Although the zodiac remains the basis of the ecliptic coordinate system
Ecliptic coordinate system
The ecliptic coordinate system is a celestial coordinate system that uses the ecliptic for its fundamental plane. The ecliptic is the path that the sun appears to follow across the celestial sphere over the course of a year. It is also the intersection of the Earth's orbital plane and the celestial...

 in use in astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

 besides the equatorial
Equatorial coordinate system
The equatorial coordinate system is a widely-used method of mapping celestial objects. It functions by projecting the Earth's geographic poles and equator onto the celestial sphere. The projection of the Earth's equator onto the celestial sphere is called the celestial equator...

 one, the term and the names of the twelve signs are today mostly associated with horoscopic astrology
Horoscopic astrology
Horoscopic astrology is a form of astrology that uses a horoscope, a visual representation of the heavens, for a specific moment in time in order to interpret the inherent meaning underlying the alignment of the planets at that moment...

.

The term "zodiac" may also refer to the region of the celestial sphere
Celestial sphere
In astronomy and navigation, the celestial sphere is an imaginary sphere of arbitrarily large radius, concentric with the Earth and rotating upon the same axis. All objects in the sky can be thought of as projected upon the celestial sphere. Projected upward from Earth's equator and poles are the...

 encompassing the paths of the planets corresponding to the band of about eight arc degrees above and below the ecliptic. The zodiac of a given planet is the band that contains the path of that particular body; e.g., the "zodiac of the Moon" is the band of five degrees above and below the ecliptic. By extension, the "zodiac of the comets" may refer to the band encompassing most short-period comets.

Early history


The division of the ecliptic into the zodiacal signs originates in Babylonia
Babylonia
Babylonia was an ancient cultural region in central-southern Mesopotamia , with Babylon as its capital. Babylonia emerged as a major power when Hammurabi Babylonia was an ancient cultural region in central-southern Mesopotamia (present-day Iraq), with Babylon as its capital. Babylonia emerged as...

n ("Chaldea
Chaldea
Chaldea or Chaldaea , from Greek , Chaldaia; Akkadian ; Hebrew כשדים, Kaśdim; Aramaic: ܟܐܠܕܘ, Kaldo) was a marshy land located in modern-day southern Iraq which came to briefly rule Babylon...

n") astronomy during the first half of the 1st millennium BCE, likely during Median/"Neo-Babylonian
Neo-Babylonian Empire
The Neo-Babylonian Empire or Second Babylonian Empire was a period of Mesopotamian history which began in 626 BC and ended in 539 BC. During the preceding three centuries, Babylonia had been ruled by their fellow Akkadian speakers and northern neighbours, Assyria. Throughout that time Babylonia...

" times (7th century BCE),
The classical zodiac is a modification of the MUL.APIN
MUL.APIN
MUL.APIN is the conventional title given to a Babylonian compendium that deals with many diverse aspects of Babylonian astronomy and astrology....

 catalogue, which was compiled around 1000 BCE.
Some of the constellations can be traced even further back, to Bronze Age (Old Babylonian) sources, including Gemini
Gemini (constellation)
Gemini is one of the constellations of the zodiac. It was one of the 48 constellations described by the 2nd century astronomer Ptolemy and it remains one of the 88 modern constellations today. Its name is Latin for "twins", and it is associated with the twins Castor and Pollux in Greek mythology...

 "The Twins", from MAŠ.TAB.BA.GAL.GAL "The Great Twins", and Cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...

 "The Crab", from AL.LUL "The Crayfish", among others.

Babylonia
Babylonia
Babylonia was an ancient cultural region in central-southern Mesopotamia , with Babylon as its capital. Babylonia emerged as a major power when Hammurabi Babylonia was an ancient cultural region in central-southern Mesopotamia (present-day Iraq), with Babylon as its capital. Babylonia emerged as...

n astronomers at some stage during the early 1st millennium BC divided the ecliptic into twelve equal zones of celestial longitude to create the first known celestial coordinate system: a coordinate system that boasts some advantages over modern systems (such as equatorial coordinate system
Equatorial coordinate system
The equatorial coordinate system is a widely-used method of mapping celestial objects. It functions by projecting the Earth's geographic poles and equator onto the celestial sphere. The projection of the Earth's equator onto the celestial sphere is called the celestial equator...

). The Babylonian calendar
Babylonian calendar
The Babylonian calendar was a lunisolar calendar with years consisting of 12 lunar months, each beginning when a new crescent moon was first sighted low on the western horizon at sunset, plus an intercalary month inserted as needed by decree. The calendar is based on a Sumerian precedecessor...

 as it stood in the 7th century BCE assigned each month to a sign, beginning with the position of the Sun at vernal equinox, which, at the time, was depicted as the Aries constellation
Aries (constellation)
Aries is one of the constellations of the zodiac, located between Pisces to the west and Taurus to the east. Its name is Latin for ram, and its symbol is , representing a ram's horns...

 ("Age of Aries"), for which reason the first constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

 is still called "Aries
Aries (astrology)
Aries is the first astrological sign in the Zodiac, which spans the zodiac between the zero degree and the 29th degree of celestial longitude. The Sun enters Aries when it reaches the northern vernal equinox, which is usually on March 21 each year, and remains in this sign until around April 20...

" even after the vernal equinox has moved away from the Aries constellation due to the slow precession of the Earth's axis of rotation.

Knowledge of the Babylonian zodiac is also reflected in the Hebrew Bible
Hebrew Bible
The Hebrew Bible is a term used by biblical scholars outside of Judaism to refer to the Tanakh , a canonical collection of Jewish texts, and the common textual antecedent of the several canonical editions of the Christian Old Testament...

. E. W. Bullinger
E. W. Bullinger
Ethelbert William Bullinger AKC was an Anglican clergyman, Biblical scholar, and ultradispensationalist theologian.-Life and work:...

 interpreted the creatures appearing in the books of Ezekiel
Book of Ezekiel
The Book of Ezekiel is the third of the Latter Prophets in the Hebrew Bible, following the books of Isaiah and Jeremiah and preceding the Book of the Twelve....

 and Revelation
Book of Revelation
The Book of Revelation is the final book of the New Testament. The title came into usage from the first word of the book in Koine Greek: apokalupsis, meaning "unveiling" or "revelation"...

 as the middle signs of the four quarters of the Zodiac, with the Lion as Leo
Leo (astrology)
Leo is the fifth astrological sign of the Zodiac, originating from the constellation of Leo. In astrology, Leo is considered to be a "masculine", positive sign. It is also considered a fire sign and is one of four fixed signs ruled by the Sun.Individuals born when the Sun is in this sign are...

, the Bull is Taurus
Taurus
Taurus is Latin for "Bull" and may refer to:* Taurus , one of the constellations of the zodiac* Bull , the mythological references around Taurus* Taurus , the astrological sign* Bos taurus, a species of cattle...

, the Man representing Aquarius and the Eagle representing Scorpio. Richard Hinckley Allen, Star Names: Their Lore and Meaning, Vol. 1 (New York: Dover Publications, 1899, p. 213-215.) argued for Scorpio having previously been called Eagle. for Scorpio. Some authors have linked the twelve tribes of Israel with the twelve signs. Martin
Ernest L. Martin
Ernest L. Martin was born in Meeker, Oklahoma who was known for his controversial works on archaeology in Israel with respect to the Temple Mount. Martin claimed that the site of the Al Aqsa mosque and Dome of the Rock incorrectly identified the true location of the Temple in Jerusalem.-Background...

 and others have argued that the arrangement of the tribes around the Tabernacle
Tabernacle
The Tabernacle , according to the Hebrew Torah/Old Testament, was the portable dwelling place for the divine presence from the time of the Exodus from Egypt through the conquering of the land of Canaan. Built to specifications revealed by God to Moses at Mount Sinai, it accompanied the Israelites...

 (reported in the Book of Numbers
Book of Numbers
The Book of Numbers is the fourth book of the Hebrew Bible, and the fourth of five books of the Jewish Torah/Pentateuch....

) corresponded to the order of the Zodiac, with Judah
Tribe of Judah
According to the Hebrew Bible, the Tribe of Judah was one of the Tribes of Israel.Following the completion of the conquest of Canaan by the Israelite tribes after about 1200 BCE, Joshua allocated the land among the twelve tribes....

, Reuben
Tribe of Reuben
According to the Hebrew Bible, the Tribe of Reuben was one of the Tribes of Israel.From after the conquest of the land by Joshua until the formation of the first Kingdom of Israel in c. 1050 BC, the Tribe of Reuben was a part of a loose confederation of Israelite tribes. No central government...

, Ephraim
Tribe of Ephraim
According to the Hebrew Bible, the Tribe of Ephraim was one of the Tribes of Israel. The Tribe of Manasseh together with Ephraim also formed the House of Joseph....

 and Dan
Tribe of Dan
The Tribe of Dan, also sometimes spelled as "Dann", was one of the Tribes of Israel. Though known mostly from biblical sources, they were possibly descendants of the Denyen Sea Peoples who joined with Hebrews...

 representing the middle signs of Leo, Aquarius, Taurus and Scorpio, respectively. Such connections were taken up by Thomas Mann
Thomas Mann
Thomas Mann was a German novelist, short story writer, social critic, philanthropist, essayist, and 1929 Nobel Prize laureate, known for his series of highly symbolic and ironic epic novels and novellas, noted for their insight into the psychology of the artist and the intellectual...

, who in his novel Joseph and His Brothers
Joseph and His Brothers
Joseph and His Brothers is a four-part novel by Thomas Mann, written over the course of 16 years. Mann retells the familiar stories of Genesis, from Jacob to Joseph , setting it in the historical context of the Amarna Period...

, attributes characteristics of a sign of the zodiac to each tribe in his rendition of the Blessing of Jacob
Blessing of Jacob
The Blessing of Jacob is a poem that appears in Genesis at . Jacob had twelve sons, each of whom is mentioned.The poem presents an opinion of the merits and attributes of each of the Tribes of Israel, and so can be compared with the Blessing of Moses, which has the same theme...

.

Hellenistic and Roman era



The Babylonian star catalogues entered Greek astronomy
Greek astronomy
Greek astronomy is astronomy written in the Greek language in classical antiquity. Greek astronomy is understood to include the ancient Greek, Hellenistic, Greco-Roman, and Late Antiquity eras. It is not limited geographically to Greece or to ethnic Greeks, as the Greek language had become the...

 in the 4th century BC, via Eudoxus of Cnidus
Eudoxus of Cnidus
Eudoxus of Cnidus was a Greek astronomer, mathematician, scholar and student of Plato. Since all his own works are lost, our knowledge of him is obtained from secondary sources, such as Aratus's poem on astronomy...

 and others.
Babylonia or Chaldea
Chaldea
Chaldea or Chaldaea , from Greek , Chaldaia; Akkadian ; Hebrew כשדים, Kaśdim; Aramaic: ܟܐܠܕܘ, Kaldo) was a marshy land located in modern-day southern Iraq which came to briefly rule Babylon...

 in the Hellenistic world came to be so identified with astrology that "Chaldean wisdom" became among Greeks
Greeks
The Greeks, also known as the Hellenes , are a nation and ethnic group native to Greece, Cyprus and neighboring regions. They also form a significant diaspora, with Greek communities established around the world....

 and Romans
Ancient Rome
Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....

 the synonym of divination
Divination
Divination is the attempt to gain insight into a question or situation by way of an occultic standardized process or ritual...

 through the planets and star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

s.
Hellenistic astrology
Hellenistic astrology
Hellenistic astrology is a tradition of horoscopic astrology that was developed and practiced in Hellenistic Egypt and the Mediterranean, whose texts were written in Greek , mainly around the late 2nd or early 1st century B.C.E...

 originated from Babylonian and Egyptian astrology.
Horoscopic astrology
Horoscopic astrology
Horoscopic astrology is a form of astrology that uses a horoscope, a visual representation of the heavens, for a specific moment in time in order to interpret the inherent meaning underlying the alignment of the planets at that moment...

 first appeared in Ptolemaic Egypt
Ptolemaic Egypt
Ptolemaic Egypt began when Ptolemy I Soter invaded Egypt and declared himself Pharaoh of Egypt in 305 BC and ended with the death of queen Cleopatra VII of Egypt and the Roman conquest in 30 BC. The Ptolemaic Kingdom was a powerful Hellenistic state, extending from southern Syria in the east, to...

. The Dendera zodiac
Dendera zodiac
The sculptured Dendera zodiac is a widely known Egyptian bas-relief from the ceiling of the pronaos of a chapel dedicated to Osiris in the Hathor temple at Dendera, containing images of Taurus and the Libra . This chapel was begun in the late Ptolemaic period; its pronaos was added by the...

, a relief dating to ca. 50 BC, is the first known depiction of the classical zodiac of twelve signs.

Particularly important in the development of Western horoscopic astrology was the astrologer and astronomer Ptolemy
Tetrabiblos
The Tetrabiblos , also known under the Latin title Quadripartitum , is a text on the philosophy and practice of astrology, written in the second century AD by the Alexandrian scholar Claudius Ptolemy ....

, whose work Tetrabiblos laid the basis of the Western astrological tradition. Under the Greeks, and Ptolemy in particular, the planets, Houses, and signs of the zodiac were rationalized and their function set down in a way that has changed little to the present day. Ptolemy lived in the 2nd century AD, three centuries after the discovery of the precession of the equinoxes
Precession of the equinoxes
In astronomy, axial precession is a gravity-induced, slow and continuous change in the orientation of an astronomical body's rotational axis. In particular, it refers to the gradual shift in the orientation of Earth's axis of rotation, which, like a wobbling top, traces out a pair of cones joined...

 by Hipparchus
Hipparchus
Hipparchus, the common Latinization of the Greek Hipparkhos, can mean:* Hipparchus, the ancient Greek astronomer** Hipparchic cycle, an astronomical cycle he created** Hipparchus , a lunar crater named in his honour...

 around 130 BC, but he ignored the problem, by dropping the concept of a fixed celestial sphere and adopting what is referred to as a tropical coordinate system instead.

Hindu zodiac


The Hindu zodiac uses the sidereal coordinate system
Sidereal astrology
Sidereal and tropical are astronomical terms used to describe two different definitions of a "year". They are also used as terms for two systems of ecliptic coordinates used in astrology....

 which makes reference to the fixed stars. The Tropical zodiac (of Mesopotamian origin), is divided by the intersections of the ecliptic
Ecliptic
The ecliptic is the plane of the earth's orbit around the sun. In more accurate terms, it is the intersection of the celestial sphere with the ecliptic plane, which is the geometric plane containing the mean orbit of the Earth around the Sun...

 and equator
Equator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....

 which shift is relation to the backdrop of fixed stars at a rate of 1° every 72 years, creating the phenomenon known as precession of the equinoxes
Precession of the equinoxes
In astronomy, axial precession is a gravity-induced, slow and continuous change in the orientation of an astronomical body's rotational axis. In particular, it refers to the gradual shift in the orientation of Earth's axis of rotation, which, like a wobbling top, traces out a pair of cones joined...

. The Hindu zodiac, being sidereal, does not maintain this seasonal alignment but there are still similarities between the two systems. The Hindu zodiac signs and corresponding Greek signs sound very different, being in Sanskrit and Greek respectively, but their symbols are nearly identical. For example, dhanu means "bow" and corresponds to Sagittarius, the "archer", and kumbha means "water-pitcher" and corresponds to Aquarius, the "water-carrier". The correspondence of signs is taken to suggest the possibility of early interchange of cultural influences.

Middle Ages and early modern period


The High Middle Ages saw a revival of Greco-Roman magic, first in Kabbalism and later continued in Renaissance magic
Renaissance magic
Renaissance humanism saw a resurgence in hermeticism and Neo-Platonic varieties of ceremonial magic.The Renaissance and the Industrial Revolution, on the other hand, saw the rise of scientism, in such forms as the substitution of chemistry for alchemy, the dethronement of the Ptolemaic theory of...

. This included magical uses of the zodiac, as found, e.g., in the Sefer Raziel HaMalakh
Sefer Raziel HaMalakh
Sefer Raziel HaMalakh, , is a medieval Kabbalistic grimoire, primarily written in Hebrew and Aramaic, but surviving also in Latin translation, as Liber Razielis Archangeli, in a 13th century manuscript produced under Alfonso X.-Textual history:The book cannot be shown to predate the 13th century,...

.

The zodiacal symbols are Early Modern simplifications of conventional pictorial representations of the signs, attested since Hellenistic times.
The symbols are encoded in Unicode
Unicode
Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...

 at positions U+2648 to U+2653 n the Miscellaneous Symbols
Miscellaneous Symbols
The Miscellaneous Symbols Unicode block contains various glyphs representing things from a variety of categories: Astrological, Astronomical, Chess, Dice, Ideological symbols, Musical notation, Political symbols, Recycling, Religious symbols, Trigrams, Warning signs and Weather.-Tables:Note: These...

 block...

The twelve signs


What follows is a list of the twelve signs of the modern zodiac (with the ecliptic longitudes of their first points), where 0° Aries is understood as the vernal equinox, with their Latin, Greek, Sanskrit, and Babylonian names (but note that the Sanskrit and the Babylonian name equivalents denote the constellations only, not the tropical zodiac signs). Also, the "English translation" is not usually used by English speakers. The Latin names are standard English usage.
Symbol Long. Latin name English translation Greek name Sanskrit name  Sumero-Babylonian name
1 Aries
Aries (astrology)
Aries is the first astrological sign in the Zodiac, which spans the zodiac between the zero degree and the 29th degree of celestial longitude. The Sun enters Aries when it reaches the northern vernal equinox, which is usually on March 21 each year, and remains in this sign until around April 20...

 
The Ram (मेष) "The Agrarian Worker", Dumuzi
2 30° Taurus
Taurus (astrology)
Taurus is the second astrological sign in the Zodiac, which spans the zodiac between the 30th and 59th degree of celestial longitude. Generally, the Sun transits this area of the zodiac between April 21 to May 21 each year...

 
The Bull (वृषभ) "The Steer of Heaven"
3 60° Gemini
Gemini (astrology)
Gemini is the third astrological sign in the Zodiac, which spans the Zodiac between the 60th and 89th degree of celestial longitude. Generally, the Sun transits this area of the zodiac between May 21 to June 20 each year...

 
The Twins (मिथुन) "The Great Twins" (Castor
Castor (star)
Castor is the second brightest star in the constellation Gemini and one of the brightest stars in the night sky. Although it has the Bayer designation "alpha", it is actually fainter than Beta Geminorum...

 and Pollux
Pollux (star)
Pollux is an orange giant star approximately 34 light-years from the Earth in the constellation of Gemini . Pollux is the brightest star in the constellation, brighter than Castor...

)
4 90° Cancer
Cancer (astrology)
Cancer is the fourth astrological sign in the Zodiac. It is considered a water sign and one of four cardinal signs. Cancer is ruled by the Moon. Individuals born when the Sun is in this sign are considered Cancerian individuals...

 
The Crab (कर्कट) "The Crayfish"
5 120° Leo
Leo (astrology)
Leo is the fifth astrological sign of the Zodiac, originating from the constellation of Leo. In astrology, Leo is considered to be a "masculine", positive sign. It is also considered a fire sign and is one of four fixed signs ruled by the Sun.Individuals born when the Sun is in this sign are...

 
The Lion (सिंह) "The Lion"
6 150° Virgo
Virgo (astrology)
Virgo is the sixth astrological sign in the Zodiac, which spans the zodiac between the 150th and 179th degree of celestial longitude. Generally, the Sun transits this area of the zodiac between August 23 to September 22 each year...

 
The Maiden (कन्या) "The Furrow"; "The Furrow, the goddess Shala
Shala
Shala is a Babylonian and Akkadian war goddess and a goddess of grain, the consort of the storm-god Adad. She carries a double-headed mace-scimitar embellished with lion heads. In the MUL.APIN, she is identified with the Virgo constellation, which was also known as "The Furrow"...

's ear of corn"
7 180° Libra
Libra (astrology)
Libra is the seventh astrological sign in the Zodiac, originating from the constellation of Libra. In astrology, Libra is considered a "masculine", positive sign. It is also considered an air sign and is one of four cardinal signs...

 
The Scales (तुला) "The Scales"
8 210° Scorpio
Scorpio (astrology)
|Infobox align="right" style="border:3px solid white;"||style="text-align: center;"|Scorpio is the eighth astrological sign in the Zodiac, which spans the zodiac between the 210th and 239th degree of celestial longitude. Generally, the Sun transits this area of the zodiac between 24 October and...

 
The Scorpion (वृश्चिक) "The Scorpion"
9 240° Sagittarius
Sagittarius (astrology)
Sagittarius is the ninth astrological sign in the Zodiac, which spans the zodiac between the 240th and 269th degree of celestial longitude...

 
The (Centaur) Archer (धनुष) , Nedu "soldier"
10 270° Capricorn  "Goat-horned" (The Sea-Goat) (मकर) "The Goat-Fish"
11 300° Aquarius  The Water-Bearer (कुम्भ) "The Great One", later "pitcher"
12 330° Pisces  The Fish (मीन) "The Tail of the Swallow", later DU.NU.NU "fish-cord"

Zodiacal constellations


It is important to distinguish the zodiacal signs
Astrological sign
Astrological signs represent twelve equal segments or divisions of the zodiac. According to astrology, celestial phenomena reflect or govern human activity on the principle of "as above, so below", so that the twelve signs are held to represent twelve basic personality types or characteristic modes...

 from the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

s associated with them, not only because of their drifting apart due to the precession of equinoxes but also because the physical constellations by nature of their varying shapes and forms take up varying widths of the ecliptic. Thus, Virgo
Virgo (constellation)
Virgo is one of the constellations of the zodiac. Its name is Latin for virgin, and its symbol is . Lying between Leo to the west and Libra to the east, it is the second largest constellation in the sky...

 takes up fully five times as much ecliptic longitude as Scorpius. The zodiacal signs, on the other hand, are an abstraction from the physical constellations designed to represent exactly one twelfth of the full circle each, or the longitude traversed by the Sun in about 30.4 days.

There have always been a number of "parazodiacal" constellations that are also touched by the paths of the planets. The MUL.APIN
MUL.APIN
MUL.APIN is the conventional title given to a Babylonian compendium that deals with many diverse aspects of Babylonian astronomy and astrology....

 lists Orion
Orion (constellation)
Orion, often referred to as The Hunter, is a prominent constellation located on the celestial equator and visible throughout the world. It is one of the most conspicuous, and most recognizable constellations in the night sky...

, Perseus
Perseus (constellation)
Perseus is a constellation in the northern sky, named after the Greek hero Perseus. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations defined by the International Astronomical Union...

, Auriga
Auriga (constellation)
Auriga is a constellation in the northern sky. Its name is Latin for 'charioteer' and its stars form a shape that has been associated with the pointed helmet of a charioteer. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains among the 88 modern...

 and Andromeda
Andromeda (constellation)
Andromeda is a constellation in the northern sky. It is named after Andromeda, the princess in the Greek legend of Perseus who was chained to a rock to be eaten by the sea monster Cetus...

. Furthermore, there are a number of constellations mythologically associated with the zodiacal ones : Piscis Austrinus
Piscis Austrinus
Piscis Austrinus is a constellation in the southern celestial hemisphere. The name is Latin for "the southern fish" in contrast with the larger constellation Pisces, which represents a pair of fishes. Prior to the 20th century, it was also known as Piscis Notius...

, The Southern Fish, is attached to Aquarius. In classical maps, it swallows the stream poured out of Aquarius' pitcher, but perhaps it formerly just swam in it. Aquila
Aquila (constellation)
Aquila is a stellar constellation. Its name is Latin for 'eagle' and it is commonly represented as such. In mythology, Aquila was owned by the Roman god Jupiter and performed many tasks for him....

, The Eagle, was possibly associated with the zodiac by virtue of its main star, Altair. Hydra
Hydra (constellation)
Hydra is the largest of the 88 modern constellations, measuring 1303 square degrees. It has a long history, having been included among the 48 constellations listed by the 2nd century astronomer Ptolemy. It is commonly represented as a water snake...

 in the Early Bronze Age marked the celestial equator
Celestial equator
The celestial equator is a great circle on the imaginary celestial sphere, in the same plane as the Earth's equator. In other words, it is a projection of the terrestrial equator out into space...

 and was associated with Leo, which is shown standing on the serpent on the Dendera zodiac
Dendera zodiac
The sculptured Dendera zodiac is a widely known Egyptian bas-relief from the ceiling of the pronaos of a chapel dedicated to Osiris in the Hathor temple at Dendera, containing images of Taurus and the Libra . This chapel was begun in the late Ptolemaic period; its pronaos was added by the...

. Corvus
Corvus (constellation)
Corvus is a small constellation in the southern sky. Its name is Latin for raven or crow. It includes only 11 stars visible to the naked eye...

 is the Crow or Raven mysteriously perched on the tail of Hydra.

Due to the constellation boundaries being redefined in 1930 by the International Astronomical Union
International Astronomical Union
The International Astronomical Union IAU is a collection of professional astronomers, at the Ph.D. level and beyond, active in professional research and education in astronomy...

, the path of the ecliptic now officially passes through thirteen constellations: the twelve traditional 'zodiac constellations' plus Ophiuchus
Ophiuchus
Ophiuchus is a large constellation located around the celestial equator. Its name is from the Greek "serpent-bearer", and it is commonly represented as a man grasping the snake that is represented by the constellation Serpens. Ophiuchus was one of the 48 constellations listed by the 2nd-century...

, the bottom part of which interjects between Scorpio and Sagittarius. Ophiuchus is an anciently recognised constellation, catalogued along with many others in Ptolemy
Ptolemy
Claudius Ptolemy , was a Roman citizen of Egypt who wrote in Greek. He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in Egypt under Roman rule, and is believed to have been born in the town of Ptolemais Hermiou in the...

's Almagest
Almagest
The Almagest is a 2nd-century mathematical and astronomical treatise on the apparent motions of the stars and planetary paths. Written in Greek by Claudius Ptolemy, a Roman era scholar of Egypt,...

, but not historically referred to as a zodiac constellation.

The technically inaccurate description of Ophiuchus as a sign of the zodiac
Astrological sign
Astrological signs represent twelve equal segments or divisions of the zodiac. According to astrology, celestial phenomena reflect or govern human activity on the principle of "as above, so below", so that the twelve signs are held to represent twelve basic personality types or characteristic modes...

 dates to the 1970s. This drew prominent media attention on 20 January 1985, following the BBC's
BBC
The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...

 opening 'Nine o'clock News' announcement that "an extra sign of the zodiac has been announced by the Royal Astronomical Society
Royal Astronomical Society
The Royal Astronomical Society is a learned society that began as the Astronomical Society of London in 1820 to support astronomical research . It became the Royal Astronomical Society in 1831 on receiving its Royal Charter from William IV...

". Investigation into the source of the story revealed there had been no such announcement, and that the report had merely sensationalised the 67-year-old 'news' of the IAU's decision to alter the number of designated ecliptic constellations. This was done for the purposes of promoting a forthcoming BBC astronomy programme, presented by the RAS's Public Relation Officer, which touched upon the topic of precession
Precession
Precession is a change in the orientation of the rotation axis of a rotating body. It can be defined as a change in direction of the rotation axis in which the second Euler angle is constant...

. The false assumption that Ophiuchus constitutes an astrological sign periodically resurfaces in the media, due to public misconception and failure to appreciate that the irregular astronomical demarcation of visible constellations does not relate to the separate frame of reference provided by the equally spaced twelve-fold longitude division of the ecliptic into zodiacal signs.

Table of dates


The following table compares the Gregorian
Gregorian calendar
The Gregorian calendar, also known as the Western calendar, or Christian calendar, is the internationally accepted civil calendar. It was introduced by Pope Gregory XIII, after whom the calendar was named, by a decree signed on 24 February 1582, a papal bull known by its opening words Inter...

 dates on which the Sun enters
  • a sign in the Ptolemaic tropical zodiac
  • a sign in the Hindu
    Jyotisha
    Hindu astrology , also Jyotish or Jyotisha, from Sanskrit , from "light, heavenly body") is the ancient Indian system of astronomy and astrology...

     sidereal
    Sidereal astrology
    Sidereal and tropical are astronomical terms used to describe two different definitions of a "year". They are also used as terms for two systems of ecliptic coordinates used in astrology....

     system
  • the astronomical constellation of the same name as the sign, with constellation boundaries as defined in 1930 by the International Astronomical Union
    International Astronomical Union
    The International Astronomical Union IAU is a collection of professional astronomers, at the Ph.D. level and beyond, active in professional research and education in astronomy...

    .


The theoretical beginning of Aries is the moment of vernal equinox, and all other dates shift accordingly.
The precise Gregorian times and dates vary slightly from year to year as the Gregorian calendar shifts relative to the tropical year
Tropical year
A tropical year , for general purposes, is the length of time that the Sun takes to return to the same position in the cycle of seasons, as seen from Earth; for example, the time from vernal equinox to vernal equinox, or from summer solstice to summer solstice...

. These variations remain within less than two days' difference in the recent past and the near-future, vernal equinox in UTC always falling either on 20 or 21 of March in the period of 1797 to 2043, falling on 19 March in 1796 the last time and in 2044 the next. In the long term, if the Gregorian calendar is not reformed, the equinox will move to earlier dates: it will fall on 18 March for the first time in AD 4092.
Sign
Astrological sign
Astrological signs represent twelve equal segments or divisions of the zodiac. According to astrology, celestial phenomena reflect or govern human activity on the principle of "as above, so below", so that the twelve signs are held to represent twelve basic personality types or characteristic modes...

Constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

Name Symbol Tropical zodiac
(2011)
Sidereal zodiac
(Jyotisha
Jyotisha
Hindu astrology , also Jyotish or Jyotisha, from Sanskrit , from "light, heavenly body") is the ancient Indian system of astronomy and astrology...

)
(2011, UTC)
Name IAU constellation 
boundaries (2011)
Solar stay Brightest star
Aries
Aries (astrology)
Aries is the first astrological sign in the Zodiac, which spans the zodiac between the zero degree and the 29th degree of celestial longitude. The Sun enters Aries when it reaches the northern vernal equinox, which is usually on March 21 each year, and remains in this sign until around April 20...

21 March –
19 April
14 April –
14 May
Aries
Aries (constellation)
Aries is one of the constellations of the zodiac, located between Pisces to the west and Taurus to the east. Its name is Latin for ram, and its symbol is , representing a ram's horns...

25.5 days Hamal
Taurus
Taurus (astrology)
Taurus is the second astrological sign in the Zodiac, which spans the zodiac between the 30th and 59th degree of celestial longitude. Generally, the Sun transits this area of the zodiac between April 21 to May 21 each year...

20 April –
20 May
14 May –
14 June
Taurus
Taurus (constellation)
Taurus is one of the constellations of the zodiac. Its name is a Latin word meaning 'bull', and its astrological symbol is a stylized bull's head:...

38.2 days Aldebaran
Aldebaran
Aldebaran is a red giant star located about 65 light years away in the zodiac constellation of Taurus. With an average apparent magnitude of 0.87 it is the brightest star in the constellation and is one of the brightest stars in the nighttime sky...

Gemini
Gemini (astrology)
Gemini is the third astrological sign in the Zodiac, which spans the Zodiac between the 60th and 89th degree of celestial longitude. Generally, the Sun transits this area of the zodiac between May 21 to June 20 each year...

21 May –
20 June
14 June –
14 July
Gemini
Gemini (constellation)
Gemini is one of the constellations of the zodiac. It was one of the 48 constellations described by the 2nd century astronomer Ptolemy and it remains one of the 88 modern constellations today. Its name is Latin for "twins", and it is associated with the twins Castor and Pollux in Greek mythology...

29.3 days Pollux
Pollux (star)
Pollux is an orange giant star approximately 34 light-years from the Earth in the constellation of Gemini . Pollux is the brightest star in the constellation, brighter than Castor...

Cancer
Cancer (astrology)
Cancer is the fourth astrological sign in the Zodiac. It is considered a water sign and one of four cardinal signs. Cancer is ruled by the Moon. Individuals born when the Sun is in this sign are considered Cancerian individuals...

21 June –
21 July
14 July –
14 August
Cancer
Cancer (constellation)
Cancer is one of the twelve constellations of the zodiac. Its name is Latin for crab and it is commonly represented as such. Its symbol is . Cancer is small and its stars are faint...

21.1 days Al Tarf
Leo
Leo (astrology)
Leo is the fifth astrological sign of the Zodiac, originating from the constellation of Leo. In astrology, Leo is considered to be a "masculine", positive sign. It is also considered a fire sign and is one of four fixed signs ruled by the Sun.Individuals born when the Sun is in this sign are...

22 July –
22 August
14 August –
13 September
Leo
Leo (constellation)
Leo is one of the constellations of the zodiac. Its name is Latin for lion. Its symbol is . Leo lies between dim Cancer to the west and Virgo to the east.-Stars:...

36.9 days Regulus
Regulus
Regulus is the brightest star in the constellation Leo and one of the brightest stars in the night sky, lying approximately 77.5 light years from Earth. Regulus is a multiple star system composed of four stars which are organized into two pairs...

Virgo
Virgo (astrology)
Virgo is the sixth astrological sign in the Zodiac, which spans the zodiac between the 150th and 179th degree of celestial longitude. Generally, the Sun transits this area of the zodiac between August 23 to September 22 each year...

23 August –
22 September
13 September –
14 October
Virgo
Virgo (constellation)
Virgo is one of the constellations of the zodiac. Its name is Latin for virgin, and its symbol is . Lying between Leo to the west and Libra to the east, it is the second largest constellation in the sky...

44.5 days Spica
Spica
Spica is the brightest star in the constellation Virgo, and the 15th brightest star in the nighttime sky. It is 260 light years distant from Earth...

Libra
Libra (astrology)
Libra is the seventh astrological sign in the Zodiac, originating from the constellation of Libra. In astrology, Libra is considered a "masculine", positive sign. It is also considered an air sign and is one of four cardinal signs...

23 September –
22 October
14 October –
13 November
Libra
Libra (constellation)
Libra is a constellation of the zodiac. Its name is Latin for weighing scales, and its symbol is . It is fairly faint, with no first magnitude stars, and lies between Virgo to the west and Scorpius to the east.-Notable features:]...

21.1 days Zubeneschamali
Scorpio
Scorpio (astrology)
|Infobox align="right" style="border:3px solid white;"||style="text-align: center;"|Scorpio is the eighth astrological sign in the Zodiac, which spans the zodiac between the 210th and 239th degree of celestial longitude. Generally, the Sun transits this area of the zodiac between 24 October and...

23 October –
21 November
13 November –
14 December
Scorpius 8.4 days Antares
Antares
Antares is a red supergiant star in the Milky Way galaxy and the sixteenth brightest star in the nighttime sky . Along with Aldebaran, Spica, and Regulus it is one of the four brightest stars near the ecliptic...

Ophiuchus
Ophiuchus (astrology)
Ophiuchus has sometimes been used in sidereal astrology as a thirteenth sign in addition to the twelve signs of the tropical Zodiac, because the eponymous constellation Ophiuchus as defined by the 1930 IAU constellation boundaries is situated behind the sun between November 29 and December 18.The...

n/a Ophiuchus 18.4 days Rasalhague/ Alpha Ophiuchi
Sagittarius
Sagittarius (astrology)
Sagittarius is the ninth astrological sign in the Zodiac, which spans the zodiac between the 240th and 269th degree of celestial longitude...

22 November –
21 December
14 December –
13 January
Sagittarius
Sagittarius (constellation)
Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow...

33.6 days Kaus Australis
Capricorn
22 December –
20 January
13 January –
12 February
Capricornus 27.4 days Deneb Algedi
Aquarius
21 January –
19 February
12 February –
14 March
Aquarius
Aquarius (constellation)
Aquarius is a constellation of the zodiac, situated between Capricornus and Pisces. Its name is Latin for "water-bearer" or "cup-bearer", and its symbol is , a representation of water....

23.9 days Sadalsuud
Pisces
20 February –
20 March
14 March –
14 April
Pisces
Pisces (constellation)
Pisces is a constellation of the zodiac. Its name is the Latin plural for fish, and its symbol is . It lies between Aquarius to the west and Aries to the east...

37.7 days Eta Piscium
Eta Piscium
Eta Piscium is the brightest star in the constellation Pisces. Eta Piscium is located at a distance of about 294 light years from Earth and shines at magnitude +3.62. It is of Spectral type G7 III...



Because the Earth's axis is at an angle, some signs take longer to rise than others, and the farther away from the equator
Equator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....

 the observer is situated, the greater the difference. Thus, signs are spoken of as "long" or "short" ascension.

Precession of the equinoxes



The zodiac system was developed in Babylonia, some 2,500 years ago, during the "Age of Aries". At the time, the precession of the equinoxes
Precession of the equinoxes
In astronomy, axial precession is a gravity-induced, slow and continuous change in the orientation of an astronomical body's rotational axis. In particular, it refers to the gradual shift in the orientation of Earth's axis of rotation, which, like a wobbling top, traces out a pair of cones joined...

 was unknown, and the system made no allowance for it. Contemporary use of the coordinate system is presented with the choice of interpreting the system either as sidereal
Sidereal astrology
Sidereal and tropical are astronomical terms used to describe two different definitions of a "year". They are also used as terms for two systems of ecliptic coordinates used in astrology....

, with the signs fixed to the stellar background, or as tropical, with the signs fixed to the point of vernal equinox.

Western astrology
Western astrology
Western astrology is the system of astrology most popular in Western countries. Western astrology is historically based on Ptolemy's Tetrabiblos , which in turn was a continuation of Hellenistic and ultimately Babylonian traditions....

 takes the tropical approach, whereas Hindu astrology takes the sidereal one. This results in the originally unified zodiacal coordinate system drifting apart gradually, with an angular velocity of about 1.4 degrees per century.

For the tropical zodiac used in Western astronomy and astrology, this means that the tropical sign of Aries currently lies somewhere within the constellation Pisces ("Age of Pisces").

The sidereal coordinate system takes into account the ayanamsa
Ayanamsa
Ayanamsa , also ayanabhāga , is the Sanskrit term in Indian astronomy for the amount of precession...

, a Sanskrit word where literally ayan means transit or movement and amsa means small part i.e. movement of equinoxes in small parts. It is unclear when Indians became aware of the precession of the equinoxes, but Bhaskar-ii in Siddhanta Shiromani gives equations for measurement of precession of equinoxes, and says his equations are based on some lost equations of Suryasiddhanta plus the equation of Munjaala.

It is not entirely clear how the Hellenistic astronomers responded to this phenomenon of precession once it had been discovered by Hipparchus
Hipparchus
Hipparchus, the common Latinization of the Greek Hipparkhos, can mean:* Hipparchus, the ancient Greek astronomer** Hipparchic cycle, an astronomical cycle he created** Hipparchus , a lunar crater named in his honour...

 around 130 BC. Today, some read Ptolemy
Ptolemy
Claudius Ptolemy , was a Roman citizen of Egypt who wrote in Greek. He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in Egypt under Roman rule, and is believed to have been born in the town of Ptolemais Hermiou in the...

 as dropping the concept of a fixed celestial sphere and adopting what is referred to as a tropical coordinate system instead: in other words, one fixed to the Earth's seasonal cycle rather than the distant stars.

Some modern Western astrologers, such as Cyril Fagan
Cyril Fagan
Cyril Fagan was an astrologer, who claimed historical use of sidereal astrology in the west and established it as a separate field from tropical astrology....

, have advocated abandoning the tropical system in favour of a sidereal one.

In modern astronomy



The zodiac is a spherical
Spherical coordinate system
In mathematics, a spherical coordinate system is a coordinate system for three-dimensional space where the position of a point is specified by three numbers: the radial distance of that point from a fixed origin, its inclination angle measured from a fixed zenith direction, and the azimuth angle of...

 celestial coordinate system
Celestial coordinate system
In astronomy, a celestial coordinate system is a coordinate system for mapping positions on the celestial sphere.There are different celestial coordinate systems each using a system of spherical coordinates projected on the celestial sphere, in analogy to the geographic coordinate system used on...

. It designates the ecliptic
Ecliptic
The ecliptic is the plane of the earth's orbit around the sun. In more accurate terms, it is the intersection of the celestial sphere with the ecliptic plane, which is the geometric plane containing the mean orbit of the Earth around the Sun...

 as its fundamental plane and the position of the Sun at Vernal equinox as its prime meridian
Prime Meridian
The Prime Meridian is the meridian at which the longitude is defined to be 0°.The Prime Meridian and its opposite the 180th meridian , which the International Date Line generally follows, form a great circle that divides the Earth into the Eastern and Western Hemispheres.An international...

.

In astronomy, the zodiacal constellations are a convenient way of marking the ecliptic (the Sun's path across the sky) and the path of the moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

 and planet
Planet
A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...

s along the ecliptic.
Modern astronomy still uses tropical coordinates for predicting the positions the Sun, Moon, and planets, except longitude in the ecliptic coordinate system
Ecliptic coordinate system
The ecliptic coordinate system is a celestial coordinate system that uses the ecliptic for its fundamental plane. The ecliptic is the path that the sun appears to follow across the celestial sphere over the course of a year. It is also the intersection of the Earth's orbital plane and the celestial...

 is numbered from 0° to 360°, not 0° to 30° within each sign. Longitude within individual signs was still being used as late as 1740 by Jacques Cassini
Jacques Cassini
Jacques Cassini was a French astronomer, son of the famous Italian astronomer Giovanni Domenico Cassini.Cassini was born at the Paris Observatory. Admitted at the age of seventeen to membership of the French Academy of Sciences, he was elected in 1696 a fellow of the Royal Society of London, and...

 in his Tables astronomiques.

Zodiac is also used to refer to the zodiacal cloud of dust grains that move among the planets and the zodiacal light
Zodiacal light
Zodiacal light is a faint, roughly triangular, whitish glow seen in the night sky which appears to extend up from the vicinity of the sun along the ecliptic or zodiac. Caused by sunlight scattered by space dust in the zodiacal cloud, it is so faint that either moonlight or light pollution renders...

 that originates from their scattering of sunlight.

Unlike the zodiac signs in astrology, which are all thirty degrees in length, the astronomical constellations vary widely in size. The boundaries of all the constellations in the sky were set by the International Astronomical Union (IAU) in 1930. This was, in essence, a mapping exercise to make the work of astronomers more efficient, and the boundaries of the constellations are not therefore in any meaningful sense an 'equivalent' to the zodiac signs. Along with the twelve original constellations, the boundaries of a thirteenth constellation, Ophiuchus
Ophiuchus
Ophiuchus is a large constellation located around the celestial equator. Its name is from the Greek "serpent-bearer", and it is commonly represented as a man grasping the snake that is represented by the constellation Serpens. Ophiuchus was one of the 48 constellations listed by the 2nd-century...

 (the serpent
Serpens
Serpens is a constellation of the northern hemisphere. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy and it remains one of the 88 modern constellations defined by the International Astronomical Union....

 bearer), were set by astronomers within the bounds of the zodiac.

Mnemonics


There are many mnemonic
Mnemonic
A mnemonic , or mnemonic device, is any learning technique that aids memory. To improve long term memory, mnemonic systems are used to make memorization easier. Commonly encountered mnemonics are often verbal, such as a very short poem or a special word used to help a person remember something,...

s for remembering the 12 signs of the zodiac in order. A traditional mnemonic:
The Ram, the Bull, the Heavenly Twins,
And next the Crab, the Lion shines,
The Virgin and the Scales.
The Scorpion, Archer, and the Goat,
The Man who holds the Watering-Pot,
And Fish with glittering scales.


A less poetic, but succinct and perhaps more memorable, mnemonic is the following:
The Ramble Twins Crab Liverish;
Scaly Scorpions Are Good Water Fish.



("Ramble" is for Ram, Bull (Aries and Taurus). "Twins" is for Gemini and "Crab" for Cancer. "Liverish" recalls Lion, Virgin (Leo and Virgo). "Scaly" recalls Scale (Libra). "Scorpion" is for Scorpio, and "Are" for Archer (Sagittarius). "Good" is for Goat (Capricorn), "Water" for the Water Bearer (Aquarius) and "Fish" for Pisces.)

Mnemonics in which the initials of the words correspond to the initials of the star signs (Latin, English, or mixed):

All The Great Constellations Live Very Long Since Stars Can't Alter Physics.


As The Great Cook Likes Very Little Salt, She Compensates Adding Pepper.


Really Boring Teachers Can Live Very Sadly Since Apples Give Worthless Feelings.


All That Gold Can Load Very Lazy Students Since Children Are at Play

See also



  • Alexander A. Gurshtein
    Alexander A. Gurshtein
    Alexander A. Gurshtein is a Russian astronomer and historian of science.Gurshtein earned his Candidate of Science from Sternberg State Astronomical Institute, Moscow in 1966 and a Doctor of Science degree in Physics & Mathematics from Pulkovo Astronomical Observatory in St...

  • Astronomical symbols
    Astronomical symbols
    Astronomical symbols are symbols used to represent various celestial objects, theoretical constructs and observational events in astronomy. The earliest forms of these symbols appear in Greek papyri of late antiquity. The Byzantine codices in which the Greek papyri were preserved continued and...

  • Circle of stars
    Circle of stars
    A Circle of stars often represents unity, solidarity and harmony in flags, seals and signs, and is also seen in iconographic motifs related to the Woman of the Apocalypse as well as in Baroque allegoric art that sometimes depicts the Crown of Immortality....

  • Cusp (astrology)
    Cusp (astrology)
    In astrology, a cusp is the imaginary line that separates a pair of consecutive signs in the zodiac or houses in the horoscope....

  • Elements of the zodiac


External links