The zodiac is a belt-shaped region of the sky that extends approximately 8° north and south celestial latitude of the

ecliptic The ecliptic or ecliptic plane is the orbital plane of Earth's orbit, Earth around the Sun. It was a central concept in a number of ancient sciences, providing the framework for key measurements in astronomy, astrology and calendar-making. Fr ...

– the apparent path of the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

across the

celestial sphere In astronomy and navigation, the celestial sphere is an abstract sphere that has an arbitrarily large radius and is concentric to Earth. All objects in the sky can be conceived as being projected upon the inner surface of the celestial sphere, ...

over the course of the year. Within this zodiac belt appear the

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

and the brightest

planet A planet is a large, Hydrostatic equilibrium, rounded Astronomical object, astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. The Solar System has eight planets b ...

s, along their orbital planes. The zodiac is divided along the ecliptic into 12 equal parts, called " signs", each occupying 30° of

celestial longitude In astronomy, coordinate systems are used for specifying positions of celestial objects (satellites, planets, stars, galaxies, etc.) relative to a given reference frame, based on physical reference points available to a situated observer (e.g. ...

. These signs roughly correspond to the

astronomical Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest include ...

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

s with the following modern names:

Aries Aries may refer to: *Aries (astrology), an astrological sign *Aries (constellation), a constellation in the zodiac Arts, entertainment and media * ''Aries'' (album), by Luis Miguel, 1993 * ''Aries'' (EP), by Alice Chater, 2020 * "Aries" (song), ...

Taurus Taurus is Latin for 'bull' and may refer to: * Taurus (astrology), the astrological sign ** Vṛṣabha, in vedic astrology * Taurus (constellation), one of the constellations of the zodiac * Taurus (mythology), one of two Greek mythological ch ...

Gemini Gemini most often refers to: * Gemini (constellation), one of the constellations of the zodiac * Gemini (astrology), an astrological sign Gemini may also refer to: Science and technology Space * Gemini in Chinese astronomy, the Gemini constellat ...

Cancer Cancer is a group of diseases involving Cell growth#Disorders, abnormal cell growth with the potential to Invasion (cancer), invade or Metastasis, spread to other parts of the body. These contrast with benign tumors, which do not spread. Po ...

Leo Leo is the Latin word for lion. It most often refers to: * Leo (constellation), a constellation of stars in the night sky * Leo (astrology), an astrological sign of the zodiac * Leo (given name), a given name in several languages, usually mas ...

Virgo Virgo may refer to: Arts and entertainment * Virgo (film), a 1970 Egyptian film * Virgo (character), several Marvel Comics characters * Virgo Asmita, a character in the manga ''Saint Seiya: The Lost Canvas'' * ''Virgo'' (album), by Virgo Four, ...

Libra Libra generally refers to: * Libra (constellation), a constellation * Libra (astrology), an astrological sign based on the star constellation Libra may also refer to: Arts and entertainment * ''Libra'' (novel), a 1988 novel by Don DeLillo Musi ...

, Scorpio, Sagittarius, Capricorn, Aquarius, and

Pisces Pisces may refer to: *Pisces (astrology), an astrological sign Astronomy *Pisces (constellation), a constellation ** Pisces Overdensity, an overdensity of stars in the Milky Way's halo that is situated in the Pisces constellation ** Pisces II, a ...

. The signs have been used to determine the time of the year by identifying each sign with the days of the year the Sun is in the respective sign. In

Western astrology Western astrology is the system of astrology most popular in Western countries. It is historically based on Ptolemy's '' Tetrabiblos'' (2nd century CE), which in turn was a continuation of Hellenistic and ultimately Babylonian traditions. West ...

, and formerly

astronomy Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest includ ...

, the time of each sign is associated with different attributes. The zodiacal system and its angular measurement in 360

sexagesimal Sexagesimal, also known as base 60, is a numeral system with 60 (number), sixty as its radix, base. It originated with the ancient Sumerians in the 3rd millennium BC, was passed down to the ancient Babylonians, and is still used—in a modified fo ...

degree (°) originated with

Babylonian astronomy Babylonian astronomy was the study or recording of celestial objects during the early history of Mesopotamia. The numeral system used, sexagesimal, was based on 60, as opposed to ten in the modern decimal system. This system simplified the ca ...

during the

1st millennium BC File:1st millennium BC.jpg, 400x400px, From top left clockwise: The Parthenon, a former temple in Athens, Greece; Aristotle, Greek philosopher; Gautama Buddha, a spiritual teacher and the founder of Buddhism; Wars of Alexander the Great last from ...

. It was communicated into

Greek astronomy Ancient Greek astronomy is the astronomy written in the Greek language during classical antiquity. Greek astronomy is understood to include the Ancient Greece, Ancient Greek, Hellenistic period, Hellenistic, Roman Empire, Greco-Roman, and Late an ...

by the 2nd century BC, as well as into developing the Hindu zodiac. Due to the

precession of the equinoxes In astronomy, axial precession is a gravity-induced, slow, and continuous change in the orientation of an astronomical body's Rotation around a fixed axis, rotational axis. In the absence of precession, the astronomical body's orbit would show ...

, the time of year that the Sun is in a given constellation has changed since Babylonian times, and the point of

March equinox The March equinox or northward equinox is the equinox on the Earth when the subsolar point appears to leave the Southern Hemisphere and cross the celestial equator, heading northward as seen from Earth. The March equinox is known as the ver ...

has moved from

into

. The zodiac forms a

celestial coordinate system In astronomy, coordinate systems are used for specifying positions of celestial objects (satellites, planets, stars, galaxies, etc.) relative to a given reference frame, based on physical reference points available to a situated observer (e. ...

, or more specifically an

ecliptic coordinate system In astronomy, 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 So ...

, which takes the ecliptic as the origin of latitude and the Sun's position at vernal equinox as the origin of longitude. In modern astronomy, the ecliptic coordinate system is still used for tracking Solar System objects.

Name

The English word ' derives from , the Latinized form of the

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

( ), meaning "cycle or circle of little animals". () is the diminutive of (, "animal"). The name reflects the prominence of animals (and

mythological hybrid Hybrid beasts are creatures composed of parts from different animals, including humans, appearing in the folklore of a variety of cultures as legendary creatures. In burial sites Remains similar to those of mythological hybrids have been found ...

s) among the twelve signs. In English, the term "zodiac" may also be used in reference to or translation for the similar twelve year cycle (also sometimes applied to other time units than years) of the East Asian-derived systems referred to as the

Chinese zodiac The Chinese zodiac is a traditional classification scheme based on the Chinese calendar that assigns an animal and its reputed attributes to each year in a repeating twelve-year (or duodenary) cycle. The zodiac is very important in traditional ...

(see also,

Earthly Branches The Earthly Branches (also called the Terrestrial Branches or the 12-cycle) are a system of twelve ordered symbols used throughout East Asia. They are indigenous to China, and are themselves Chinese characters, corresponding to words with no co ...

): similarities include the use of animal or theriomorphic figures associated with a twelve year cycle used culturally to allege or describe personality traits, life events, and their interrelationships—thus this use in translation.

Usage

The zodiac was in use by the

Roman era In modern historiography, ancient Rome is the Roman people, Roman civilisation from the founding of Rome, founding of the Italian city of Rome in the 8th century BC to the Fall of the Western Roman Empire, collapse of the Western Roman Em ...

, based on concepts inherited by

Hellenistic astronomy Ancient Greek astronomy is the astronomy written in the Greek language during classical antiquity. Greek astronomy is understood to include the Ancient Greek, Hellenistic, Greco-Roman, and late antique eras. Ancient Greek astronomy can be divided ...

from

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 Claudius Ptolemy (; , ; ; – 160s/170s AD) was a Greco-Roman mathematician, astronomer, astrologer, geographer, and music theorist who wrote about a dozen scientific treatises, three of which were important to later Byzantine science, Byzant ...

's comprehensive 2nd century AD work, the ''

Almagest The ''Almagest'' ( ) is a 2nd-century Greek mathematics, mathematical and Greek astronomy, astronomical treatise on the apparent motions of the stars and planetary paths, written by Ptolemy, Claudius Ptolemy ( ) in Koine Greek. One of the most i ...

''. Although the zodiac remains the basis of the

in use in

besides the equatorial one, the term and the names of the twelve signs are today mostly associated with

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 to interpret the purported meaning behind the alignment of the planets at that moment. The idea is that the pl ...

. The term "zodiac" may also refer to the region of the

encompassing the paths of the planets corresponding to the band of about 8 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 5° above and below the ecliptic. By extension, the "zodiac of the comets" may refer to the band encompassing most short-period comets.

History

Early history

As early as the 14th century BC a complete list of the 36 Egyptian

decan The decans (; Egyptian ''bꜣktw'' or ''baktiu'', "

hose A hose is a flexible hollow tube or pipe designed to carry fluids from one location to another, often from a faucet or hydrant. Early hoses were made of leather, although modern hoses are typically made of rubber, canvas, and helically wound w ...

connected with work") are 36 groups of stars (small constellations) used in the Egyptian astronomy, ancient Egyptian astronomy to conveniently divide the 360 degree ecliptic into 36 parts ...

s was placed among the hieroglyphs adorning the tomb of

Seti I Menmaatre Seti I (or Sethos I in Greek language, Greek) was the second pharaoh of the Nineteenth Dynasty of Egypt during the New Kingdom of Egypt, New Kingdom period, ruling or 1290 BC to 1279 BC. He was the son of Ramesses I and Sitre, and th ...

; they figured again in the temple of

Ramesses II Ramesses II (sometimes written Ramses or Rameses) (; , , ; ), commonly known as Ramesses the Great, was an Pharaoh, Egyptian pharaoh. He was the third ruler of the Nineteenth Dynasty of Egypt, Nineteenth Dynasty. Along with Thutmose III of th ...

, and characterize every Egyptian astrological monument. Both the famous zodiacs of

Dendera Dendera ( ''Dandarah''; ; Bohairic ; Sahidic ), also spelled ''Denderah'', ancient Iunet 𓉺𓈖𓏏𓊖 “jwn.t”, Tentyris,(Arabic: Ewan-t إيوان-ة ), or Tentyra is a small town and former bishopric in Egypt situated on the west bank of ...

display their symbols, identified by

Karl Richard Lepsius Karl Richard Lepsius (; 23 December 181010 July 1884) was a German people, Prussian Egyptology, Egyptologist, Linguistics, linguist and modern archaeology, modern archaeologist. He is widely known for his opus magnum ''Denkmäler aus Ägypten ...

Antoninus Pius Drachm showing a Zodiac wheel

The division of the ecliptic into the zodiacal signs originates in

during the first half of the

. The zodiac draws on stars in earlier

Babylonian star catalogues Babylonian astronomy collated earlier observations and divinations into sets of Babylonian star catalogues, during and after the Kassite rule over Babylonia. These star catalogues, written in cuneiform script, contained lists of constellations, ...

, such as the MUL.APIN catalogue, which was compiled around 1000 BC. Some constellations can be traced even further back, to Bronze Age (

Old Babylonian Empire The Old Babylonian Empire, or First Babylonian Empire, is dated to , and comes after the end of Sumerian power with the destruction of the Third Dynasty of Ur, and the subsequent Isin-Larsa period. The chronology of the first dynasty of Babylon ...

) sources, including

"The Twins", from "The Great Twins";

"The Crab", from "The Crayfish", among others. Around the end of the fifth century BC,

Babylonia Babylonia (; , ) was an Ancient history, ancient Akkadian language, Akkadian-speaking state and cultural area based in the city of Babylon in central-southern Mesopotamia (present-day Iraq and parts of Kuwait, Syria and Iran). It emerged as a ...

n astronomers divided the ecliptic into 12 equal "signs", by analogy to 12 schematic months of 30 days each. Each sign contained 30° of

, thus creating the first known celestial coordinate system. According to calculations by modern astrophysics, the zodiac was introduced between 409 and 398 BC, during Persian rule, and probably within a very few years of 401 BC. Unlike modern astrologers, who place the beginning of the sign of

at the position of the Sun at the vernal equinox in the

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the equator. For other planets in the Solar System, north is defined by humans as being in the same celestial sphere, celestial hemisphere relative to the invariable plane of the Solar ...

(

), Babylonian astronomers fixed the zodiac in relation to stars, placing the beginning of

at the "Rear Twin Star" ( β Geminorum) and the beginning of Aquarius at the "Rear Star of the Goat-Fish" ( δ Capricorni). Due to the

, the time of year the Sun is in a given constellation has changed since Babylonian times, as the point of March equinox has moved from

into

. Because the divisions were made into equal arcs of 30° each, they constituted an ideal system of reference for making predictions about a planet's longitude. However, Babylonian techniques of observational measurements were in a rudimentary stage of evolution. They measured the position of a planet in reference to a set of "normal stars" close to the ecliptic (±9° of latitude). The normal stars were used as observational reference points to help position a planet within this ecliptic coordinate system. In

Babylonian astronomical diaries The Babylonian astronomical diaries are a collection of Babylonian cuneiform texts written in Akkadian language that contain systematic records of astronomical observations and political events, predictions based on astronomical observations, weat ...

, a planet position was generally given with respect to a zodiacal sign alone, though less often in specific degrees within a sign. When the degrees of longitude were given, they were expressed with reference to the 30° of the zodiacal sign, i.e., not with a reference to the continuous 360° ecliptic. In astronomical

ephemerides In astronomy and celestial navigation, an ephemeris (; ; , ) is a book with tables that gives the trajectory of naturally occurring astronomical objects and artificial satellites in the sky, i.e., the position (and possibly velocity) over time. ...

, the positions of significant astronomical phenomena were computed in

fractions of a degree (equivalent to

minutes and seconds of arc A minute of arc, arcminute (abbreviated as arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of a degree. Since one degree is of a turn, or complete rotation, one arcminute is of a tu ...

). For daily ephemerides, the daily positions of a planet were not as important as the astrologically significant dates when the planet crossed from one zodiacal sign to the next.

Hebrew astronomy and astrology

Knowledge of the Babylonian zodiac is said to be reflected in the

Hebrew Bible The Hebrew Bible or Tanakh (;"Tanach"
. '' E. W. Bullinger interpreted the creatures that appear in the

book of Ezekiel The Book of Ezekiel is the third of the Nevi'im#Latter Prophets, Latter Prophets in the Hebrew Bible, Tanakh (Hebrew Bible) and one of the Major Prophets, major prophetic books in the Christian Bible, where it follows Book of Isaiah, Isaiah and ...

( 1:10) as the middle signs of the four quarters of the zodiac, with the Lion as

, the Bull as

, the Man as Aquarius and the Eagle as a higher aspect of Scorpio. Some authors have linked the signs of the zodiac with the

twelve tribes of Israel The Twelve Tribes of Israel ( , ) are described in the Hebrew Bible as being the descendants of Jacob, a Patriarchs (Bible), Hebrew patriarch who was a son of Isaac and thereby a grandson of Abraham. Jacob, later known as Israel (name), Israel, ...

, and with the lunar

Hebrew calendar The Hebrew calendar (), also called the Jewish calendar, is a lunisolar calendar used today for Jewish religious observance and as an official calendar of Israel. It determines the dates of Jewish holidays and other rituals, such as '' yahrze ...

, which has twelve

lunar months In lunar calendars, a lunar month is the time between two successive syzygies of the same type: new moons or full moons. The precise definition varies, especially for the beginning of the month. Variations In Shona, Middle Eastern, and Euro ...

in a

lunar year A lunar calendar is a calendar based on the monthly cycles of the Moon's phases (synodic months, lunations), in contrast to solar calendars, whose annual cycles are based on the solar year, and lunisolar calendars, whose lunar months are brought ...

Martin Martin may refer to: Places Antarctica * Martin Peninsula, Marie Byrd Land * Port Martin, Adelie Land * Point Martin, South Orkney Islands Europe * Martin, Croatia, a village * Martin, Slovakia, a city * Martín del Río, Aragón, Spain * M ...

and others have argued that the arrangement of the tribes around the

Tabernacle According to the Hebrew Bible, the tabernacle (), also known as the Tent of the Congregation (, also Tent of Meeting), was the portable earthly dwelling of God used by the Israelites from the Exodus until the conquest of Canaan. Moses was instru ...

(reported in the

Book of Numbers The Book of Numbers (from Biblical Greek, Greek Ἀριθμοί, ''Arithmoi'', , ''Bəmīḏbar'', ; ) is the fourth book of the Hebrew Bible and the fourth of five books of the Jewish Torah. The book has a long and complex history; its final f ...

) corresponded to the order of the zodiac, with Judah,

Reuben Reuben or Reuven is a Biblical male first name from Hebrew רְאוּבֵן (Re'uven), meaning "behold, a son". In the Bible, Reuben was the firstborn son of Jacob. Variants include Reuvein in Yiddish or as an English variant spelling on th ...

Ephraim Ephraim (; , in pausa: ''ʾEp̄rāyīm'') was, according to the Book of Genesis, the second son of Joseph ben Jacob and Asenath, as well as the adopted son of his biological grandfather Jacob, making him the progenitor of the Tribe of Ephrai ...

, and Dan representing the middle signs of Leo, Aquarius, Taurus, and Scorpio, respectively. Such connections were taken up by

Thomas Mann Paul Thomas Mann ( , ; ; 6 June 1875 – 12 August 1955) was a German novelist, short story writer, social critic, philanthropist, essayist, and the 1929 Nobel Prize in Literature laureate. His highly symbolic and ironic epic novels and novell ...

, who in his novel ''

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 (chapters 27–50), setting it in the historical context of the ...

'', attributes characteristics of a sign of the zodiac to each tribe, in his rendition of the

Blessing of Jacob The Blessing of Jacob is a prophetic poem that appears written in Genesis at and mentions each of Jacob's twelve sons. Genesis presents the poem to be the words of Jacob himself to his sons when he is about to die. Linguistically, it's dated t ...

Hellenistic and Roman era

The Babylonian star catalogs entered

in the 4th century BC, via

Eudoxus of Cnidus Eudoxus of Cnidus (; , ''Eúdoxos ho Knídios''; ) was an Ancient Greece, ancient Greek Ancient Greek astronomy, astronomer, Greek mathematics, mathematician, doctor, and lawmaker. He was a student of Archytas and Plato. All of his original work ...

. Babylonia or

Chaldea Chaldea () refers to a region probably located in the marshy land of southern Mesopotamia. It is mentioned, with varying meaning, in Neo-Assyrian cuneiform, the Hebrew Bible, and in classical Greek texts. The Hebrew Bible uses the term (''Ka� ...

in the Hellenistic world came to be so identified with astrology that "Chaldean wisdom" became among

Greeks Greeks or Hellenes (; , ) are an ethnic group and nation native to Greece, Greek Cypriots, Cyprus, Greeks in Albania, southern Albania, Greeks in Turkey#History, Anatolia, parts of Greeks in Italy, Italy and Egyptian Greeks, Egypt, and to a l ...

and

Romans Roman or Romans most often refers to: *Rome, the capital city of Italy *Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of Roman civilization *Epistle to the Romans, shortened to Romans, a letter w ...

the synonym of

divination Divination () is the attempt to gain insight into a question or situation by way of an occultic ritual or practice. Using various methods throughout history, diviners ascertain their interpretations of how a should proceed by reading signs, ...

through the

planets A planet is a large, rounded astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. The Solar System has eight planets by the most restrictive definition of the te ...

and

star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...

Hellenistic astrology Hellenistic astrology is a tradition of horoscopic astrology that was developed and practiced in the late Hellenistic period in and around the Mediterranean Basin region, especially in Egypt. The texts and technical terminology of this tradition ...

derived in part from Babylonian and Egyptian 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 to interpret the purported meaning behind the alignment of the planets at that moment. The idea is that the pl ...

first appeared in

Ptolemaic Egypt Ptolemaic is the adjective formed from the name Ptolemy, and may refer to: Pertaining to the Ptolemaic dynasty * Ptolemaic dynasty, the Macedonian Greek dynasty that ruled Egypt founded in 305 BC by Ptolemy I Soter *Ptolemaic Kingdom Pertaining ...

(305 BC–30 BC). The

Dendera zodiac The sculptured Dendera zodiac (or Denderah zodiac) is a widely known Art of ancient Egypt, Egyptian bas-relief from the ceiling of the ''pronaos'' (or portico) of a chapel dedicated to Osiris in the Dendera Temple complex, Hathor temple at Dende ...

, a relief dating to , is the first known depiction of the classical zodiac of twelve signs. The earliest extant Greek text using the Babylonian division of the zodiac into 12 signs of 30 equal degrees each is the ''Anaphoricus'' of Hypsicles of Alexandria (fl.190BC). Particularly important in the development of Western horoscopic astrology was the astrologer and astronomer

, 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 Precession is a change in the orientation of the rotational axis of a rotating body. In an appropriate reference frame it can be defined as a change in the first Euler angle, whereas the third Euler angle defines the rotation itself. In o ...

of the equinoxes by

Hipparchus Hipparchus (; , ; BC) was a Ancient Greek astronomy, Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry, but is most famous for his incidental discovery of the precession of the equinoxes. Hippar ...

around 130 BC. Hipparchus' lost work on precession never circulated very widely until it was brought to prominence by Ptolemy, and there are few explanations of precession outside the work of Ptolemy until late Antiquity, by which time Ptolemy's influence was widely established. Ptolemy clearly explained the theoretical basis of the western zodiac as being a tropical coordinate system, by which the zodiac is aligned to the equinoxes and solstices, rather than the visible constellations that bear the same names as the zodiac signs.

Hindu zodiac

According to mathematician-historian Montucla, the Hindu zodiac was adopted from the Greek zodiac through communications between ancient India and the Greek empire of

Bactria Bactria (; Bactrian language, Bactrian: , ), or Bactriana, was an ancient Iranian peoples, Iranian civilization in Central Asia based in the area south of the Oxus River (modern Amu Darya) and north of the mountains of the Hindu Kush, an area ...

. The Hindu zodiac uses the sidereal coordinate system, which makes reference to the fixed stars. The tropical zodiac (of Mesopotamian origin) is divided by the intersections of the

and

equator The equator is the circle of latitude that divides Earth into the Northern Hemisphere, Northern and Southern Hemisphere, Southern Hemispheres of Earth, hemispheres. It is an imaginary line located at 0 degrees latitude, about in circumferen ...

, which shifts in relation to the backdrop of fixed stars at a rate of 1° every 72 years, creating the phenomenon known as precession of the equinoxes. 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".

Middle Ages

Angers Cathedral South Rose Window of Christ with Zodiac

During the Abbasid era, Greek reference books were translated into

Arabic Arabic (, , or , ) is a Central Semitic languages, Central Semitic language of the Afroasiatic languages, Afroasiatic language family spoken primarily in the Arab world. The International Organization for Standardization (ISO) assigns lang ...

, and Islamic astronomers then did their own observations, correcting Ptolemy's Almagest. One such book was

Al-Sufi ʿAbd al-Raḥmān al-Ṣūfī (; 7 December 90325 May 986) was a Persian astronomer. His work '' '' ("''The Book of Fixed Stars''"), written in 964, included both textual descriptions and illustrations. The Persian polymath Al-Biruni wrote th ...

's ''

Book of Fixed Stars ''The Book of Fixed Stars'' ( ', literally ''The Book of the Shapes of Stars'') is an Astronomy, astronomical text written by Abd al-Rahman al-Sufi (Azophi) around 964. Following Graeco-Arabic translation movement, the translation movement in the ...

'', which has pictorial depictions of 48 constellations. The book was divided into three sections: constellations of the zodiac, constellations north of the zodiac, and southern constellations. When Al-Sufi's book, and other works, were translated in the 11th century, there were mistakes made in the translations. As a result, some stars ended up with the names of the constellation they belong to (e.g.

Hamal Hamal, pronounced , is a star in the northern zodiacal constellation of Aries. It has the Bayer designation Alpha Arietis, which is Latinized from α Arietis and abbreviated Alpha Ari or α Ari. This star is visible to the naked eye wit ...

in Aries). The High Middle Ages saw a revival of interest in Greco-Roman magic, first in Kabbalism and later continued in

Renaissance magic Renaissance magic was a resurgence in Hermeticism and Neoplatonic varieties of the magical arts which arose along with Renaissance humanism in the 15th and 16th centuries CE. During the Renaissance period, magic and occult practices underwent s ...

. This included magical uses of the zodiac, as found, e.g., in the

Sefer Raziel HaMalakh ''Sefer Raziel HaMalakh'' (, "the book of Raziel the angel") is a grimoire of Practical Kabbalah from the Middle Ages written primarily in Hebrew and Aramaic. ''Liber Razielis Archangeli'', its 13th-century Latin translation produced under Alf ...

. The zodiac is found in medieval

stained glass Stained glass refers to coloured glass as a material or art and architectural works created from it. Although it is traditionally made in flat panels and used as windows, the creations of modern stained glass artists also include three-dimensio ...

as at Angers Cathedral, where the master glass maker, André Robin, made the ornate rosettes for the North and South transepts after the fire there in 1451.

Medieval Islamic era

Ottoman Sundial at the Debbane Palace museum

Astrology Astrology is a range of Divination, divinatory practices, recognized as pseudoscientific since the 18th century, that propose that information about human affairs and terrestrial events may be discerned by studying the apparent positions ...

emerged in the 8th century AD as a distinct discipline in Islam, with a mix of Indian, Hellenistic Iranian and other traditions blended with Greek and Islamic astronomical knowledge, for example Ptolemy's work and Al-Sufi's Book of Fixed Stars. A knowledge of the influence that the stars have on events on the earth was important in Islamic civilization. As a rule, it was believed that the signs of the zodiac and the planets control the destiny not only of people but also of nations, and that the zodiac has the ability to determine a person's physical characteristics as well as intelligence and personal traits. The practice of astrology at this time could be divided into four broader categories:

Genethlialogy Natal astrology, also known as genethliac astrology or genethlialogy, is a system of astrology that claims to shed light on an individual’s personality or path in life based on constructing a horoscope or natal chart that includes the exact da ...

, Catarchic Astrology, Interrogational Astrology and General Astrology. However the most common type of astrology was Genethlialogy, which examined all aspects of a person's life in relation to the planetary positions at their birth; more commonly known as our horoscope. Astrology services were offered widely across the empire, mainly in bazaars, where people could pay for a reading. Astrology was valued in the royal courts, for example, the Abbasid Caliph Al-Mansur used astrology to determine the best date for founding the new capital of Baghdad. While horoscopes were generally widely accepted by society, many scholars condemned the use of astrology and divination, linking it to occult influences. Many theologians and scholars thought that it went against the tenets of Islam; as only God should be able to determine events rather than astrologers looking at the positions of the planets. In order to calculate someone's horoscope, an astrologer would use three tools: an astrolabe, ephemeris and a takht. First, the astrologer would use an astrolabe to find the position of the sun, align the rule with the persons time of birth and then align the rete to establish the altitude of the sun on that date. Next, the astrologer would use an ephemeris, a table denoting the mean position of the planets and stars within the sky at any given time. Finally, the astrologer would add the altitude of the sun taken from the astrolabe, with the mean position of the planets on the person's birthday, and add them together on the takht (also known as the dustboard). The dust board was merely a tablet covered in sand; on which the calculations could be made and erased easily. Once this had been calculated, the astrologer was then able to interpret the horoscope. Most of these interpretations were based on the zodiac in literature. For example, there were several manuals on how to interpret each zodiac sign, the treatise relating to each individual sign and what the characteristics of these zodiacs were.

Early modern

An example of the use of signs as astronomical coordinates may be found in the ''Nautical Almanac and Astronomical Ephemeris for the year 1767''. The "Longitude of the Sun" columns show the sign (represented as a digit from 0 to and including 11), degrees from 0 to 29, minutes, and seconds. Mughal king

Jahangir Nur-ud-din Muhammad Salim (31 August 1569 – 28 October 1627), known by his imperial name Jahangir (; ), was List of emperors of the Mughal Empire, Emperor of Hindustan from 1605 until his death in 1627, and the fourth Mughal emperors, Mughal ...

issued an attractive series of coins in gold and silver depicting the twelve signs of the zodiac. File:P.9 a volvella of the moon. A volvella is a moveable device for working out the position of the sun and moon in the zodiac.jpg, A volvella of the moon. A volvella is a moveable device for working out the position of the Sun and Moon in the zodiac, 15th century File:Monasterio de Svetitskhoveli, Miskheta, Georgia, 2016-09-29, DD 41.jpg, 17th-century fresco of

Christ Jesus ( AD 30 or 33), also referred to as Jesus Christ, Jesus of Nazareth, and many other names and titles, was a 1st-century Jewish preacher and religious leader. He is the Jesus in Christianity, central figure of Christianity, the M ...

in the zodiac circle, Cathedral of Living Pillar,

Georgia Georgia most commonly refers to: * Georgia (country), a country in the South Caucasus * Georgia (U.S. state), a state in the southeastern United States Georgia may also refer to: People and fictional characters * Georgia (name), a list of pe ...

Twelve signs

What follows is a list of the 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 the Sanskrit and the name equivalents (after c.500 BC) denote the constellations only, not the tropical zodiac signs. The "English translation" is not usually used by English speakers. The Latin names are standard English usage (except that "Capricorn" is used rather than "Capricornus"). These twelve signs have been arranged into a nursery rhyme as a mnemonic device: Another mnemonic is ''A Tense Gray Cat Lay Very Low, Sneaking Slowly, Contemplating A Pounce''. The following table compares the Gregorian dates on which the Sun enters a sign in the Ptolemaic

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

zodiac, and a sign in two sidereal systems: one proposed by

Cyril Fagan Cyril Fagan ( Dublin, Ireland, May 22, 1896 – Tucson, Arizona, United States, January 5, 1970) was an Irish astrologer, Generally considered ''the father'' - alongside Donald A. Bradley, ''the mother'', of the western sidereal astrology In ...

, and a fourteen-sign system proposed by Steven Schmidt which adds

Ophiuchus Ophiuchus () is a large constellation straddling the celestial equator. Its name comes from the Ancient Greek (), meaning "serpent-bearer", and it is commonly represented as a man grasping a snake. The serpent is represented by the constellati ...

(see below) and

Cetus Cetus () is a constellation, sometimes called 'the whale' in English. The Cetus (mythology), Cetus was a sea monster in Greek mythology which both Perseus and Heracles needed to slay. Cetus is in the region of the sky that contains other water- ...

(the

IAU The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...

boundaries of which just graze by the ecliptic): Zodiac German Woodcut

The beginning of Aries is defined as 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 The Gregorian calendar is the calendar used in most parts of the world. It went into effect in October 1582 following the papal bull issued by Pope Gregory XIII, which introduced it as a modification of, and replacement for, the Julian cale ...

shifts relative to the

tropical year A tropical year or solar year (or tropical period) is the time that the Sun takes to return to the same position in the sky – as viewed from the Earth or another celestial body of the Solar System – thus completing a full cycle of astronom ...

. These variations remain within less than two days' difference in the recent past and the near-future, vernal equinox in UT always falling either on 20 or 21 March in the period of 1797 to 2043, falling on 19 March in 1796 the last time and in 2044 the next. The vernal equinox has fallen on 20 March UT since 2008, and will continue to do so until 2043.

As each sign takes up exactly 30 degrees of the zodiac, the average duration of the solar stay in each sign is one twelfth of a

sidereal year A sidereal year (, ; ), also called a sidereal orbital period, is the time that Earth or another planetary body takes to orbit the Sun once with respect to the fixed stars. Hence, for Earth, it is also the time taken for the Sun to return to t ...

, or 30.43 standard

day A day is the time rotation period, period of a full Earth's rotation, rotation of the Earth with respect to the Sun. On average, this is 24 hours (86,400 seconds). As a day passes at a given location it experiences morning, afternoon, evening, ...

s. Due to Earth's slight

orbital eccentricity In astrodynamics, the orbital eccentricity of an astronomical object is a dimensionless parameter that determines the amount by which its orbit around another body deviates from a perfect circle. A value of 0 is a circular orbit, values be ...

, the duration of each sign varies appreciably, between about 29.4 days for Capricorn and about 31.4 days for Cancer (see

Equation of time The equation of time describes the discrepancy between two kinds of solar time. The two times that differ are the apparent solar time, which directly tracks the diurnal motion of the Sun, and mean solar time, which tracks a theoretical mean Sun ...

). In addition, because the Earth's axis is at an angle, some signs take longer to rise than others, and the farther away from the equator the observer is situated, the greater the difference. Thus, signs are spoken of as "long" or "short" ascension.

Constellations

tropical astrology In astrology, ''Sidereal time, sidereal'' and ''Tropical year, tropical'' are terms that refer to two different systems of Ecliptic coordinate system, ecliptic coordinates used to divide the ecliptic into twelve "signs". Each sign is divided int ...

, the zodiacal signs are distinct from the

s associated with them, not only because of their drifting apart due to the precession of equinoxes but because the physical constellations take up varying widths of the ecliptic, so the Sun is not in each constellation for the same amount of time. Thus,

takes up 5 times as much

ecliptic longitude In astronomy, 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 So ...

Scorpius Scorpius is a zodiac constellation located in the Southern celestial hemisphere, where it sits near the center of the Milky Way, between Libra to the west and Sagittarius to the east. Scorpius is an ancient constellation whose recognition pred ...

. The zodiacal signs are an abstraction from the physical constellations, and each represent exactly th of the full circle, but the time spent by the Sun in each sign varies slightly due to the eccentricity of the

Earth's orbit Earth orbits the Sun at an astronomical unit, average distance of , or 8.317 light-second, light-minutes, in a retrograde and prograde motion, counterclockwise direction as viewed from above the Northern Hemisphere. One complete orbit takes & ...

Sidereal astrology In astrology, '' sidereal'' and ''tropical'' are terms that refer to two different systems of ecliptic coordinates used to divide the ecliptic into twelve "signs". Each sign is divided into 30 degrees, making a total of 360 degrees. The terms si ...

assigns the zodiac sign approximately to the corresponding constellation. This alignment needs recalibrating every so often to keep the alignment in place. The ecliptic intersects with 13 constellations of

's ''

'', as well as of the more precisely delineated

IAU designated constellations In contemporary astronomy, 88 constellations are recognized by the International Astronomical Union (IAU). Each constellation is a region of the sky bordered by arcs of right ascension and declination, together covering the entire celestial sph ...

. In addition to the twelve constellations after which the twelve zodiac signs are named, the ecliptic intersects

, the bottom part of which interjects between Scorpius and Sagittarius. Occasionally this difference between the astronomical constellations and the

astrological sign In Western astrology, astrological signs are the twelve 30-degree sectors that make up ecliptic, Earth's 360-degree orbit around the Sun. The signs enumerate from the first day of spring, known as the First Point of Aries, which is the Equinox (c ...

s is mistakenly reported in the popular press as a "change" to the list of traditional signs by some astronomical body like the IAU,

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

, or the

Royal Astronomical Society The Royal Astronomical Society (RAS) is a learned society and charitable organisation, charity that encourages and promotes the study of astronomy, planetary science, solar-system science, geophysics and closely related branches of science. Its ...

. This happened in a 1995 report of the ''

BBC Nine O'Clock News The ''BBC Nine O'Clock News'' is a news programme that was BBC News' flagship for more than thirty years. It was launched on 14 September 1970 and ran until 13 October 2000, when it was replaced by '' BBC Ten O'Clock News'' (later ''BBC News a ...

'' and various reports in 2011 and 2016. Some "parazodiacal" constellations are touched by the paths of the planets, leading to counts of up to 25 "constellations of the zodiac". The ancient Babylonian MUL.APIN catalog lists Orion,

Perseus In Greek mythology, Perseus (, ; Greek language, Greek: Περσεύς, Romanization of Greek, translit. Perseús) is the legendary founder of the Perseid dynasty. He was, alongside Cadmus and Bellerophon, the greatest Greek hero and slayer of ...

Auriga Auriga is a constellation in the northern celestial hemisphere. It is one of the 88 modern constellations; it was among the 48 constellations listed by the 2nd-century astronomer Ptolemy. Its name is Latin for '(the) charioteer', associating i ...

, and Andromeda. Modern astronomers have noted that planets pass through

Crater A crater is a landform consisting of a hole or depression (geology), depression on a planetary surface, usually caused either by an object hitting the surface, or by geological activity on the planet. A crater has classically been described ...

Sextans Sextans is a faint, minor constellation on the celestial equator which was introduced in 1687 by Polish astronomer Johannes Hevelius. Its name is Latin for the astronomical sextant, an instrument that Hevelius made frequent use of in his obs ...

Pegasus Pegasus (; ) is a winged horse in Greek mythology, usually depicted as a white stallion. He was sired by Poseidon, in his role as horse-god, and foaled by the Gorgon Medusa. Pegasus was the brother of Chrysaor, both born from Medusa's blood w ...

Corvus ''Corvus'' is a widely distributed genus of passerine birds ranging from medium-sized to large-sized in the family Corvidae. It includes species commonly known as crows, ravens, and rooks. The species commonly encountered in Europe are the car ...

, Hydra, Orion, and

Scutum The ''scutum'' (; :''scuta'') was a type of shield used among Italic peoples in antiquity, most notably by the army of ancient Rome starting about the fourth century BC. The Romans adopted it when they switched from the military formation of ...

, with

Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...

very rarely passing through Aquila,

Canis Minor Canis Minor is a small constellation in the Celestial sphere, northern celestial hemisphere. In the second century, it was included as an Asterism (astronomy), asterism, or pattern, of two stars in Ptolemy's 48 constellations, and it is counte ...

, and

Serpens Serpens () is a constellation in the northern celestial hemisphere. One of the 48 constellations listed by the 2nd-century astronomer Ptolemy, it remains one of the 88 modern constellations designated by the International Astronomical Union. It ...

. Some other constellations are mythologically associated with the zodiacal ones:

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 fish. Before the 20th century, it was also known as ...

, 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, The Eagle, was possibly associated with the zodiac by virtue of its main star,

Altair Altair is the brightest star in the constellation of Aquila (constellation), Aquila and the list of brightest stars, twelfth-brightest star in the night sky. It has the Bayer designation Alpha Aquilae, which is Latinisation of name ...

. Hydra in the Early Bronze Age marked the

celestial equator The celestial equator is the great circle of the imaginary celestial sphere on the same plane as the equator of Earth. By extension, it is also a plane of reference in the equatorial coordinate system. Due to Earth's axial tilt, the celestial ...

and was associated with Leo, which is shown standing on the serpent on the

Precession of the equinoxes

The zodiac system was developed in

, some 2,500 years ago, during the " Age of Aries". At the time, it is assumed, the precession of the equinoxes was unknown. Contemporary use of the coordinate system is presented with the choice of interpreting the system either as sidereal, with the signs fixed to the stellar background, or as

, with the signs fixed to the point (

vector Vector most often refers to: * Euclidean vector, a quantity with a magnitude and a direction * Disease vector, an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematics a ...

of the Sun) at the

takes the tropical approach, whereas Hindu astrology takes the sidereal one. This results in the originally unified zodiacal coordinate system drifting apart gradually, with a clockwise (westward) precession of 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, ''ayan'' meaning "transit" or "movement", and ''amsa'' meaning 'small part', i.e. movement of equinoxes in small parts. It is unclear when Indians became aware of the precession of the equinoxes, but

Bhāskara II Bhāskara II ('; 1114–1185), also known as Bhāskarāchārya (), was an Indian people, Indian polymath, Indian mathematicians, mathematician, astronomer and engineer. From verses in his main work, Siddhānta Śiromaṇi, it can be inferre ...

's 12th-century treatise '' Siddhanta Shiromani'' gives equations for measurement of precession of equinoxes, and says his equations are based on some lost equations of ''

Suryasiddhanta The ''Surya Siddhanta'' (; ) is a Sanskrit treatise in Indian astronomy dated to 4th to 5th century,Menso Folkerts, Craig G. Fraser, Jeremy John Gray, John L. Berggren, Wilbur R. Knorr (2017)Mathematics Encyclopaedia Britannica, Quote: "(...) i ...

'' plus the equation of Munjaala. The discovery of precession is attributed to Hipparchus around 130 BC. Ptolemy quotes from Hipparchus' now-lost work entitled "On the Displacement of the Solstitial and Equinoctial Points" in the seventh book of his 2nd century astronomical text, ''Almagest'', where he describes the phenomenon of precession and estimates its value. Ptolemy clarified that the convention of Greek mathematical astronomy was to commence the zodiac from the point of the vernal equinox and to always refer to this point as "the first degree" of Aries. This is known as the "tropical zodiac" (from the Greek word trópos, turn) because its starting point revolves through the circle of background constellations over time. The principle of the vernal point acting as the first degree of the zodiac for Greek astronomers is described in the 1st century BC astronomical text of

Geminus Geminus of Rhodes (), was a Greek astronomer and mathematician, who flourished in the 1st century BC. An astronomy work of his, the ''Introduction to the Phenomena'', still survives; it was intended as an introductory astronomy book for students ...

of Rhodes. Geminus explains that Greek astronomers of his era associate the first degrees of the zodiac signs with the two solstices and the two equinoxes, in contrast to the older Chaldean (Babylonian) system, which placed these points within the zodiac signs. This illustrates that Ptolemy merely clarified the convention of Greek astronomers and did not originate the principle of the tropical zodiac, as is sometimes assumed. Ptolemy demonstrates that the principle of the tropical zodiac was well known to his predecessors within his astrological text, the ''

Tetrabiblos ''Tetrabiblos'' (, ), also known as ''Apotelesmatiká'' (, ) and in Latin as ''Quadripartitum'' (), is a text on the philosophy and practice of astrology, written by the Alexandrian scholar Claudius Ptolemy in Koine Greek during the Ptolemy' ...

'', where he explains why it would be an error to associate the regularly spaced signs of the seasonally aligned zodiac with the irregular boundaries of the visible constellations:

In modern astronomy

Astronomically, the zodiac defines a belt of space extending 8° or 9° in celestial latitude to the north and south of the

, within which the orbits of the Moon and the principal planets remain. It is a feature of the ecliptic coordinate system – a

centered upon the ecliptic (the plane of the Earth's orbit and the Sun's apparent path), by which

is measured in degrees east of the vernal equinox (the ascending intersection of the ecliptic and equator). The zodiac is narrow in angular terms because most of the Sun's planets have orbits that have only a slight

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Eart ...

to the

orbital plane The orbital plane of a revolving body is the geometric plane in which its orbit lies. Three non-collinear points in space suffice to determine an orbital plane. A common example would be the positions of the centers of a massive body (host) a ...

of the Earth. Stars within the zodiac are subject to

occultation An occultation is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in astronomy, but can also refer to any situation in which an object in the foreground blocks f ...

s by the Moon and other solar system bodies. These events can be useful, for example, to estimate the cross-sectional dimensions of a

minor planet According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...

, or check a star for a close companion. Zodiacal Light Seen from Paranal

The Sun's placement upon the vernal equinox, which occurs annually around 21 March, defines the starting point for measurement, the first degree of which is historically known as the " first point of Aries". The first 30° along the ecliptic is nominally designated as the zodiac sign Aries, which no longer falls within the proximity of the constellation Aries since the effect of precession is to move the vernal point through the backdrop of visible constellations. It is currently located near the end of the constellation Pisces, having been within that constellation since the 2nd century AD. The subsequent 30° of the ecliptic is nominally designated the zodiac sign Taurus, and so on through the twelve signs of the zodiac so that each occupies th (30°) of the zodiac's great circle. Zodiac signs have never been used to determine the boundaries of astronomical constellations that lie in the vicinity of the zodiac, which are, and always have been, irregular in their size and shape. The convention of measuring celestial longitude within individual signs was still being used in the mid-19th century, but modern astronomy now numbers degrees of celestial longitude continuously from 0° to 360°, rather than 0° to 30° within each sign. This coordinate system is primary used by astronomers for observations of solar system objects. The use of the zodiac as a means to determine astronomical measurement remained the main method for defining celestial positions by Western astronomers until the Renaissance, at which time preference moved to the equatorial coordinate system, which measures astronomical positions by

right ascension Right ascension (abbreviated RA; symbol ) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the equinox (celestial coordinates), March equinox to the (hour circle of the) point in questio ...

and

declination In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. The declination angle is measured north (positive) or ...

rather than the ecliptic-based definitions of celestial longitude and celestial latitude. The orientation of equatorial coordinates are aligned with the Earth's axis of rotation, rather than the plane of the planet's orbit around the Sun. The word "zodiac" is used in reference to the zodiacal cloud of dust grains that move among the planets, and the

zodiacal light The zodiacal light (also called false dawn when seen before sunrise) is a faint glow of diffuse sunlight scattered by interplanetary dust. Brighter around the Sun, it appears in a particularly dark night sky to extend from the Sun's direct ...

that originates from their scattering of sunlight. While its name is derived from the zodiac, the zodiacal light covers the entire night sky, with enhancements in certain directions.

Unicode characters

In Unicode, the symbols of zodiac signs are encoded in block "Miscellaneous Symbols". They can be forced to look like text by appending U+FE0E, or like emojis by appending U+FE0F:

References

External links

"A Treatise on Zodiacal Signs and Constellations: Unique Jewels on the Benefits of Keeping Time"
– a manuscript that dates back to 1831 with a focus on Arabic, Coptic and Syriac calendars. {{DEFAULTSORT:Zodiac, The Z + Ancient astronomy Astrology Astronomical coordinate systems Birthdays Early scientific cosmologies Western astrology