A cartoon is a type of visual art that is typically drawn, frequently animated, in an unrealistic or semi-realistic style. The specific meaning has evolved, but the modern usage usually refers to either: an image or series of images intended for satire, caricature, or humor; or a motion picture that relies on a sequence of illustrations for its animation. Someone who creates cartoons in the first sense is called a cartoonist,[1] and in the second sense they are usually called an animator.
The concept originated in the Middle Ages, and first described a preparatory drawing for a piece of art, such as a painting, fresco, tapestry, or stained glass window. In the 19th century, beginning in Punch magazine in 1843, cartoon came to refer – ironically at first – to humorous artworks in magazines and newspapers. Then it also was used for political cartoons and comic strips. When the medium developed, in the early 20th century, it began to refer to animated films that resembled print cartoons.[2]
Fine art
Christ’s Charge to Peter, one of the Raphael Cartoons, c. 1516, a full-size cartoon design for a tapestry
In fine art, a cartoon (from Italian: cartone and Dutch: karton—words describing strong, heavy paper or pasteboard and cognates for carton) is a full-size drawing made on sturdy paper as a design or modello for a painting, stained glass, or tapestry. Cartoons were typically used in the production of frescoes, to accurately link the component parts of the composition when painted on damp plaster over a series of days (giornate).[3] In media such as stained tapestry or stained glass, the cartoon was handed over by the artist to the skilled craftsmen who produced the final work.
Such cartoons often have pinpricks along the outlines of the design so that a bag of soot patted or “pounced” over a cartoon, held against the wall, would leave black dots on the plaster (“pouncing”). Cartoons by painters, such as the Raphael Cartoons in London, Francisco Goya’s tapestry cartoons, and examples by Leonardo da Vinci, are highly prized in their own right. Tapestry cartoons, usually colored, could be placed behind the loom, where the weaver would replicate the design. As tapestries are worked from behind, a mirror could be placed behind the loom to allow the weaver to see their work; in such cases the cartoon was placed behind the weaver.[2][4]
Mass media
John Leech, Substance and Shadow (1843), published as Cartoon, No. 1 in Punch, the first use of the word cartoon to refer to a satirical drawing
In print media, a cartoon is a drawing or series of drawings, usually humorous in intent. This usage dates from 1843, when Punch magazine applied the term to satirical drawings in its pages,[5] particularly sketches by John Leech.[6] The first of these parodied the preparatory cartoons for grand historical frescoes in the then-new Palace of Westminster in London.[7]
Bill Hoest, Jerry Marcus, and Virgil Partch began as magazine gag cartoonists and moved to syndicated comic strips. Richard Thompson illustrated numerous feature articles in The Washington Post before creating his Cul de Sac comic strip. The sports section of newspapers usually featured cartoons, sometimes including syndicated features such as Chester “Chet” Brown’s All in Sport.
Editorial cartoons are found almost exclusively in news publications and news websites. Although they also employ humor, they are more serious in tone, commonly using irony or satire. The art usually acts as a visual metaphor to illustrate a point of view on current social or political topics. Editorial cartoons often include speech balloons and sometimes use multiple panels. Editorial cartoonists of note include Herblock, David Low, Jeff MacNelly, Mike Peters, and Gerald Scarfe.[2]
Comic strips, also known as cartoon strips in the United Kingdom, are found daily in newspapers worldwide, and are usually a short series of cartoon illustrations in sequence. In the United States, they are not commonly called “cartoons” themselves, but rather “comics” or “funnies“. Nonetheless, the creators of comic strips—as well as comic books and graphic novels—are usually referred to as “cartoonists“. Although humor is the most prevalent subject matter, adventure and drama are also represented in this medium. Some noteworthy cartoonists of humorous comic strips are Scott Adams, Charles Schulz, E. C. Segar, Mort Walker and Bill Watterson.[2]
Political cartoons are like illustrated editorials that serve visual commentaries on political events. They offer subtle criticism which are cleverly quoted with humour and satire to the extent that the criticized does not get embittered.
The pictorial satire of William Hogarth is regarded as a precursor to the development of political cartoons in 18th century England.[11]George Townshend produced some of the first overtly political cartoons and caricatures in the 1750s.[11][12] The medium began to develop in the latter part of the 18th century under the direction of its great exponents, James Gillray and Thomas Rowlandson, both from London. Gillray explored the use of the medium for lampooning and caricature, and has been referred to as the father of the political cartoon.[13] By calling the king, prime ministers and generals to account for their behaviour, many of Gillray’s satires were directed against George III, depicting him as a pretentious buffoon, while the bulk of his work was dedicated to ridiculing the ambitions of revolutionary France and Napoleon.[13]George Cruikshank became the leading cartoonist in the period following Gillray, from 1815 until the 1840s. His career was renowned for his social caricatures of English life for popular publications.
Nast depicts the Tweed Ring: “Who stole the people’s money?” / “‘Twas him.”
By the mid 19th century, major political newspapers in many other countries featured cartoons commenting on the politics of the day. Thomas Nast, in New York City, showed how realistic German drawing techniques could redefine American cartooning.[14] His 160 cartoons relentlessly pursued the criminal characteristic of the Tweed machine in New York City, and helped bring it down. Indeed, Tweed was arrested in Spain when police identified him from Nast’s cartoons.[15] In Britain, Sir John Tenniel was the toast of London.[16] In France under the July Monarchy, Honoré Daumier took up the new genre of political and social caricature, most famously lampooning the rotund King Louis Philippe.
Political cartoons can be humorous or satirical, sometimes with piercing effect. The target of the humor may complain, but can seldom fight back. Lawsuits have been very rare; the first successful lawsuit against a cartoonist in over a century in Britain came in 1921, when J. H. Thomas, the leader of the National Union of Railwaymen (NUR), initiated libel proceedings against the magazine of the British Communist Party. Thomas claimed defamation in the form of cartoons and words depicting the events of “Black Friday”, when he allegedly betrayed the locked-out Miners’ Federation. To Thomas, the framing of his image by the far left threatened to grievously degrade his character in the popular imagination. Soviet-inspired communism was a new element in European politics, and cartoonists unrestrained by tradition tested the boundaries of libel law. Thomas won the lawsuit and restored his reputation.[17]
Scientific
Cartoons such as xkcd have also found their place in the world of science, mathematics, and technology. For example, the cartoon Wonderlab looked at daily life in the chemistry lab. In the U.S., one well-known cartoonist for these fields is Sidney Harris. Many of Gary Larson‘s cartoons have a scientific flavor.
The first comic-strip cartoons were of a humorous tone.[18] Notable early humor comics include the Swiss comic-strip book Mr. Vieux Bois (1837), the British strip Ally Sloper (first appearing in 1867) and the American strip Yellow Kid (first appearing in 1895).
In the United States in the 1930s, books with cartoons were magazine-format “American comic books” with original material, or occasionally reprints of newspaper comic strips.[19]
In Britain in the 1930s, adventure comic magazines became quite popular, especially those published by DC Thomson; the publisher sent observers around the country to talk to boys and learn what they wanted to read about. The story line in magazines, comic books and cinema that most appealed to boys was the glamorous heroism of British soldiers fighting wars that were exciting and just.[20] DC Thomson issued the first The Dandy Comic in December 1937. It had a revolutionary design that broke away from the usual children’s comics that were published broadsheet in size and not very colourful. Thomson capitalized on its success with a similar product The Beano in 1938.[21]
On some occasions, new gag cartoons have been created for book publication.
Because of the stylistic similarities between comic strips and early animated films, cartoon came to refer to animation, and the word cartoon is currently used in reference to both animated cartoons and gag cartoons.[22] While animation designates any style of illustrated images seen in rapid succession to give the impression of movement, the word “cartoon” is most often used as a descriptor for television programs and short films aimed at children, possibly featuring anthropomorphized animals,[23]superheroes, the adventures of child protagonists or related themes.
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, and formerly astronomy, the time of each sign is associated with different attributes. The zodiacal system and its angular measurement in 360 sexagesimaldegree (°) originated with Babylonian astronomy during the 1st millennium BC. It was communicated into Greek astronomy by the 2nd century BC, as well as into developing the Hindu zodiac. Due to the precession of the equinoxes, the time of year that the Sun is in a given constellation has changed since Babylonian times, and the point of March equinox has moved from Aries into Pisces.
The English word zodiac derives from zōdiacus,[5] the Latinized form of the Ancient Greekzōdiakòs kýklos (ζῳδιακόςκύκλος),[6] meaning “cycle or circle of little animals”. Zōdion (ζῴδιον) is the diminutive of zōon (ζῷον, “animal”).[7] The name reflects the prominence of animals (and mythological hybrids) 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 (see also, Earthly Branches): similarities include the use of animal or theriomorphic figures associated with a twelve year cycle used culturally to allege or describe personality traits and/or life events, and their interrelationships — thus this use in translation.
The zodiac was 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.[8] The construction of the zodiac is described in Ptolemy‘s comprehensive 2nd century AD work, the Almagest.[9]
Although the zodiac remains the basis of the ecliptic coordinate system in use in astronomy besides the equatorial one,[10][11] the term and the names of the twelve signs are today mostly associated with horoscopic astrology.[12] The term “zodiac” may also refer to the region of the celestial sphere 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.[13]
As early as the 14th century BC a complete list of the 36 Egyptian decans was placed among the hieroglyphs adorning the tomb of Seti I; they figured again in the temple of Ramesses II, and characterize every Egyptian astrological monument. Both the famous zodiacs of Dendera display their symbols, identified by Karl Richard Lepsius.[14]
Roman Egyptian coin of Antoninus Pius (dated year 8 of his reign or 145 AD) showing his portrait and a Zodiac wheel with the busts of Helios and Selene in the centerA sixth-century mosaic zodiac wheel in synagogue Beth Alpha incorporating Greek-Byzantine elements, IsraelZodiac circle with planets, c. 1000 – NLW MS 735C
The division of the ecliptic into the zodiacal signs originates in Babylonian astronomy during the first half of the 1st millennium BC. The zodiac draws on stars in earlier Babylonian star catalogues, 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) sources, including Gemini “The Twins”, from Sumerian: 𒀯𒈦𒋰𒁀𒃲𒃲, romanized: MULMAŠ.TAB.BA.GAL.GAL “The Great Twins”; Cancer “The Crab”, from Sumerian: 𒀯𒀠𒇻, romanized: MULAL.LUL “The Crayfish”, among others.[15][16]
Around the end of the fifth century BC, Babylonian astronomers divided the ecliptic into 12 equal “signs”, by analogy to 12 schematic months of 30 days each. Each sign contained 30° of celestial longitude, 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,[17] and probably within a very few years of 401 BC.[18] Unlike modern astrologers, who place the beginning of the sign of Aries at the position of the Sun at the vernal equinox in the Northern Hemisphere (March equinox), Babylonian astronomers fixed the zodiac in relation to stars, placing the beginning of Cancer at the “Rear Twin Star” (β Geminorum) and the beginning of Aquarius at the “Rear Star of the Goat-Fish” (δ Capricorni).[19]
Due to the precession of the equinoxes, 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 Aries into Pisces.[20]
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.[21] 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.[22]
In Babylonian astronomical diaries, a planet position was generally given with respect to a zodiacal sign alone, though less often in specific degrees within a sign.[23] 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.[23] In astronomical ephemerides, the positions of significant astronomical phenomena were computed in sexagesimal fractions of a degree (equivalent to minutes and seconds of arc).[24] 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.[23]
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. 190 BC).[29] Particularly important in the development of Western horoscopic astrology was the astrologer and astronomer Ptolemy, whose work Tetrabiblos laid the basis of the Western astrological tradition.[30] 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.[31] Ptolemy lived in the 2nd century AD, three centuries after the discovery of the precession of the equinoxes by Hipparchus around 130 BC. Hipparchus’ lost work on precession never circulated very widely until it was brought to prominence by Ptolemy,[32] and there are few explanations of precession outside the work of Ptolemy until late Antiquity, by which time Ptolemy’s influence was widely established.[33] 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.[34]
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.[35] 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 ecliptic and equator, 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.[36] For example, dhanu means “bow” and corresponds to Sagittarius, the “archer”, and kumbha means “water-pitcher” and corresponds to Aquarius, the “water-carrier”.[37]
Angers Cathedral South Rose Window of Christ (center) with elders (bottom half) and zodiac (top half). Medieval stained glass by Andre Robin after the fire of 1451
During the Abbasid era, Greek reference books were translated into Arabic, and Islamic astronomers then did their own observations, correcting Ptolemy’s Almagest. One such book was Al-Sufi‘s Book of Fixed Stars, 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 in Aries).
The zodiac is found in medieval stained glass 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.[38]
Ottoman-style sundial with folded gnomon and compass. The sundial features engraved toponyms in Arabic and zodiac symbols. Debbane Palace museum, Lebanon
Astrology emerged in the 8th century AD as a distinct discipline in Islam,[39]: 64 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.[40]
The practice of astrology at this time could be divided into 4 broader categories: Genethlialogy, Catarchic Astrology, Interrogational Astrology and General Astrology.[39]: 65 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.[39]: 65
Astrology services were offered widely across the empire, mainly in bazaars, where people could pay for a reading.[41] 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.[39]: 66 Whilst horoscopes were generally widely accepted by society, many scholars condemned the use of astrology and divination, linking it to occult influences.[42] 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.[41]
In order to calculate someone’s horoscope, an astrologer would use 3 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.[43] 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.[44] 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).[44] The dust board was merely a tablet covered in sand; on which the calculations could be made and erased easily.[41] 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.[41]
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.[45]
Mughal kingJahangir issued an attractive series of coins in gold and silver depicting the twelve signs of the zodiac.[46]
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
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”).
MULSIM.MAḪ “Tail of the Swallow”; DU.NU.NU “fish-cord”
These twelve signs have been arranged into a nursery rhyme as a mnemonic device:[51]
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.
Another mnemonic is A Tense Gray Cat Lay Very Low, Sneaking Slowly, Contemplating A Pounce.[52][53]
The following table compares the Gregorian dates on which the Sun enters a sign in the Ptolemaic tropical zodiac, and a sign in two sidereal systems: one proposed by Cyril Fagan, and a fourteen-sign system proposed by Steven Schmidt which adds Ophiuchus (see below) and Cetus (the IAU boundaries of which just graze by the ecliptic):
The zodiac signs in a 16th-century woodcut
The beginning of Aries is defined as the moment of vernal equinox, and all other dates shift accordingly.[54] The precise Gregorian times and dates vary slightly from year to year as the Gregorian calendar shifts relative to the tropical year. 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.[55]
Depiction of the southern hemisphere constellations in an 11th-century French manuscript (from the Limoges area, probably in the milieu of Adémar de Chabannes, fl. 1020–1034)
^ Jump up to:abcSchmidt (1970) added a Sun sign for Cetus, falling between Aries and Taurus from May 12 – June 6, as well as the more often seen addition of Ophiuchus, q.v.[ii]. However, his symbols for Cetus and Ophiuchus are not the same as the symbols used here. Under the IAU constellation boundaries, the sign of Cetus corresponds to the half of Taurus mostly west of Aldebaran and the Hyades, while the Taurus sign corresponds to the half of Taurus east of Aldebaran and the Hyades.
^ Jump up to:ab Ophiuchus is not a sign in traditional forms of tropical and sidereal astrology, and only appears in a few forms of astrology which use the nominal constellation boundaries adopted by the IAU.
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, or 30.43 standard days. Due to Earth’s slight orbital eccentricity, 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). 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.[62]
These two maps of the constellations, made two centuries apart, both show the zodiac constellations along a curved line representing the ecliptic.
18th-century star chart illustrating the feet of Ophiuchus crossing the ecliptic
In tropical astrology, the zodiacal signs are distinct from the constellations 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.[63]: 25 Thus, Virgo takes up 5 times as much ecliptic longitude as Scorpius. The zodiacal signs are an abstraction from the physical constellations, and each represent exactly 1⁄12th 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.
Sidereal astrology 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 Ptolemy‘s Almagest,[64] as well as of the more precisely delineated IAU designated constellations. In addition to the twelve constellations after which the twelve zodiac signs are named, the ecliptic intersects Ophiuchus,[65] the bottom part of which interjects between Scorpius and Sagittarius. Occasionally this difference between the astronomical constellations and the astrological signs is mistakenly reported in the popular press as a “change” to the list of traditional signs by some astronomical body like the IAU, NASA, or the Royal Astronomical Society. This happened in a 1995 report of the BBC Nine O’Clock News and various reports in 2011 and 2016.[66][67][68]
Some other constellations are mythologically associated with the zodiacal ones: Piscis Austrinus, 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. Hydra in the Early Bronze Age marked the celestial equator and was associated with Leo, which is shown standing on the serpent on the Dendera zodiac.[15]
Path taken by the point of the March equinox along the ecliptic over the past 6,000 years
The zodiac system was developed in Babylonia, some 2,500 years ago, during the “Age of Aries“.[21] 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 tropical, with the signs fixed to the point (vector of the Sun) at the March equinox.[23]
Western astrology 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‘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 plus the equation of Munjaala.[citation needed]
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.[32] 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.[71] This is known as the “tropical zodiac” (from the Greek word trópos, turn)[72] 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 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.[71] 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, 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:
The beginnings of the signs, and likewise those of the terms, are to be taken from the equinoctial and tropical points. This rule is not only clearly stated by writers on the subject, but is especially evident by the demonstration constantly afforded, that their natures, influences and familiarities have no other origin than from the tropics and equinoxes, as has been already plainly shown. And, if other beginnings were allowed, it would either be necessary to exclude the natures of the signs from the theory of prognostication, or impossible to avoid error in then retaining and making use of them; as the regularity of their spaces and distances, upon which their influence depends, would then be invaded and broken in upon.[34]
Two false dawns,[73]gegenschein (middle) and the rest of the zodiacal band of the zodiacal light, with the zodiac marked (visually crossed by the Milky Way), in this composite image of the night sky above the northern and southern hemisphere
Astronomically, the zodiac defines a belt of space extending 8°[74] or 9° in celestial latitude to the north and south of the ecliptic, within which the orbits of the Moon and the principal planets remain.[75] It is a feature of the ecliptic coordinate system – a celestial coordinate system centered upon the ecliptic (the plane of the Earth’s orbit and the Sun’s apparent path), by which celestial longitude is measured in degrees east of the vernal equinox (the ascending intersection of the ecliptic and equator).[76] The zodiac is narrow in angular terms because most of the Sun’s planets have orbits that have only a slight inclination to the orbital plane of the Earth.[77] Stars within the zodiac are subject to occultations 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, or check a star for a close companion.[78]
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.[79] 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 1⁄12th (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.[75]
The convention of measuring celestial longitude within individual signs was still being used in the mid-19th century,[80] but modern astronomy now numbers degrees of celestial longitude continuously from 0° to 360°, rather than 0° to 30° within each sign.[81] This coordinate system is primary used by astronomers for observations of solar system objects.[82]
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 and declination 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.[79]
The word “zodiac” is used in reference to the zodiacal cloud of dust grains that move among the planets, and the zodiacal light that originates from their scattering of sunlight.[83] While its name is derived from the zodiac, the zodiacal light covers the entire night sky, with enhancements in certain directions.[84]
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:[85]
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