Classical Greco-Roman mythology and Roman mythology or Greco-Roman mythology is both the body of and the study of myths from the ancient Greeks and Romans as they are used or transformed by cultural reception. Along with philosophy and political thought, mythology represents one of the major survivals of classical antiquity throughout Western culture; the Greek word mythos refers to the spoken word or speech, but it denotes a tale, story or narrative. Classical mythology has provided subject matter for all forms of visual and literary art in the West, including poetry, painting, sculpture and ballet, as well as forms of popular culture such as Hollywood movies, television series, comic books, video games. Classical myths are alluded to in scientific naming in astronomy and biology, in the psychoanalytic theory of Freud and the archetypal psychology of Jung. During the Middle Ages and Renaissance, when Latin remained the dominant language in Europe for international educated discourse, mythological names always appeared in Latinized form.
With the Greek revival of the 19th century, Greek names began to be used more with both "Zeus" and "Jove" being used as the name of the supreme god of the classical pantheon. Classical mythology is a term used to designate the myths belonging to the Greek and Roman traditions; the myths are believed to have been acquired first by oral tradition, entering since Homer and Hesiod the literate era. A classical myth as it appears in Western culture is a syncretism of various versions from both Greek and Latin sources. Greek myths were narratives related to ancient Greek religion concerned with the actions of gods and other supernatural beings and of heroes who transcend human bounds. Major sources for Greek myths include the Homeric epics, that is, the Iliad and the Odyssey, the tragedies of Aeschylus and Euripides. Known versions are preserved in sophisticated literary works shaped by the artistry of individuals and by the conventions of genre, or in vase painting and other forms of visual art. In these forms, mythological narratives serve purposes that are not religious, such as entertainment and comedy, or the exploration of social issues.
Roman myths are traditional stories pertaining to ancient Rome's legendary origins, religious institutions, moral models, with a focus on human actors and only occasional intervention from deities but a pervasive sense of divinely ordered destiny. Roman myths have a dynamic relation to Roman historiography, as in the early books of Livy's Ab urbe condita; the most famous Roman myth may be the birth of Romulus and Remus and the founding of the city, in which fratricide can be taken as expressing the long history of political division in the Roman Republic. During the Hellenization of Roman literature and culture, the Romans identified their own gods with those of the Greeks, adapting the stories told about them and importing other myths for which they had no counterpart. For instance, while the Greek god Ares and the Italic god Mars are both war deities, the role of each in his society and its religious practices differed strikingly; the literary collection of Greco-Roman myths with the greatest influence on Western culture was the Metamorphoses of the Augustan poet Ovid.
Syncretized versions form the classical tradition of mythography, by the time of the influential Renaissance mythographer Natalis Comes, few if any distinctions were made between Greek and Roman myths. The myths as they appear in popular culture of the 20th and 21st centuries have only a tangential relation to the stories as told in ancient Greek and Latin literature. Chariot clock Classical tradition Classics Greco-Roman world Greek mythology in western art and literature LGBT themes in classical mythology List of films based on Greco-Roman mythology List of films based on Greek drama Matter of Rome Natale Conti, influential Renaissance mythographer Proto-Indo-European religion Vatican Mythographers Greco-Roman mythology in popular culture Greek Antiquity in art and culture Greco-Roman mythology in Marvel Comics Greco-Roman mythology in DC Comics Video games based on mythology Operas based on Greco-Roman mythology Ares in popular culture Icarus imagery in contemporary music Prometheus in popular culture
Mount Olympus is the highest mountain in Greece. It is located in the Olympus Range on the border between Thessaly and Macedonia, between the regional units of Pieria and Larissa, about 80 km southwest from Thessaloniki. Mount Olympus has 52 peaks, deep gorges, exceptional biodiversity; the highest peak, meaning "nose", rises to 2,919 metres. It is one of the highest peaks in Europe in terms of topographic prominence. Olympus is notable in Greek mythology on Mytikas peak. Mount Olympus is noted for its rich flora, it has been a National Park, the first in Greece, since 1938. It is a World Biosphere Reserve; every year, thousands of people visit Olympus to admire its fauna and flora, tour its slopes, reach its peaks. Organized mountain refuges and various mountaineering and climbing routes are available to visitors who want to explore it; the usual starting point for climbing Olympus is the town of Litochoro, on the eastern foothills of the mountain, 100 km from Thessaloniki. The shape of Olympus was formed by rain and wind, which produced an isolated tower 3,000 metres above the sea, only 18 kilometres away at Litochoro.
Olympus has many peaks and an circular shape. The mountain has a circumference of 150 kilometres, an average diameter of 26 kilometres, 500 square kilometres of area. To the northwest lies the Vlach village of Kokkinoplou; the Makryrema stream separates Olympus from the massif of Voulgara. The villages Petra and Dion lie to the northwest, while on the eastern side there is the town of Litochoro, where Enipeas bisects the massif of Olympus. On its southeastern side, the Ziliana gorge divides Mount Olympus from Kato Olympos, while on its southwestern foothills, there are the villages Sykaminea and Karya; the Agia Triada Sparmou Monastery and the village Pythion lie to the west. Olympus' dry foothills, known as the Xirokampi, are covered in chaparral and provides habitat for animals such as wild boar. Further east, the plain of Dion watered by the streams which originate on Olympus. Mount Olympus is formed of sedimentary rock laid down 200 million years ago in a shallow sea. Various geological events that followed caused the emergence of the sea.
Around one million years ago glaciers created its plateaus and depressions. With the temperature rise that followed, the ice melted and the streams that were created swept away large quantities of crushed rock in the lowest places, forming the alluvial fans, that spread out all over the region from the foothills of the mountain to the sea; the Geological Museum of Mount Olympus, located in Leptokarya, provides detailed information about the geological structure of the mountain. The complicated geological past of the region is obvious from the morphology of Olympus and its National Park. Features include deep gorges and dozens of smooth peaks, many of them in altitude of more than 2,000 metres, including Aghios Antonios, Kalogeros and Profitis Ilias. However, it is the central vertical, rocky peaks, that impress the visitor. Over the town of Litochoro, on the horizon, the relief of the mountain displays an apparent V, between two peaks of equal height; the left limb is the peak named Mytikas. It is Greece's highest peak.
On the right is Stefani, which presents the most impressive and steep peak of Olympus, with its last rising 200 meters presenting the greatest challenge for climbers. Further south, Skolio completes an arc of about 200 degrees, with its steep slopes forming on the west side, like a wall, an impressive precipitous amphitheatrical cavity, 700 metres in depth and 1,000 metres in circumference, the'Megala Kazania'. On the east side of the high peaks the steep slopes form zone like parallel folds, the'Zonaria'. Narrower and steeper scorings, the'Loukia', lead to the peak. Οn the north side, between Stefani and Profitis Ilias, extends the Muses' Plateau, at 2,550 metres, while further south in the center of the massif, extends the alpine tundra region of Bara, at an altitude of 2,350 metres. Olympus has numerous gullies. Most distinguishable of the ravines are those of Mavrologos-Enipeas and Mavratzas-Sparmos near Bara and'cut' the massif in two oval portions. On the southern foothills the great gorge of Ziliana, 13 km long, consists of a natural limit that separates the mountain from Lower Olympus.
There are many precipices and a number of caves nowadays unexplored. The form and layout of the rocks favor the emergence of numerous springs lower than 2,000 m, of small seasonal lakes and streams and of a small river, with its springs in the site Prionia and its estuary in the Aegean Sea; the origin of the name Όλυμπος Olumpos is unknown and considered of "pre-Greek" origin. In Homeric Greek, the variant Οὔλυμπος Oulumpos occurs. Homer appears to be using οὔλυμπος as a common noun, as a synonym of οὐρανός ouranos "sky". Mt Olympus was also known as Mount Belus, after Iliad 1.591, where the seat of the gods is referred to as βηλ θεσπεσίο "heavenly threshold". In Ancient Greek religion and myth
A constellation is a group of stars that forms an imaginary outline or pattern on the celestial sphere representing an animal, mythological person or creature, a god, or an inanimate object. The origins of the earliest constellations go back to prehistory. People used them to relate stories of their beliefs, creation, or mythology. Different cultures and countries adopted their own constellations, some of which lasted into the early 20th century before today's constellations were internationally recognized. Adoption of constellations has changed over time. Many have changed in shape; some became popular. Others were limited to single nations; the 48 traditional Western constellations are Greek. They are given in Aratus' work Phenomena and Ptolemy's Almagest, though their origin predates these works by several centuries. Constellations in the far southern sky were added from the 15th century until the mid-18th century when European explorers began traveling to the Southern Hemisphere. Twelve ancient constellations belong to the zodiac.
The origins of the zodiac remain uncertain. In 1928, the International Astronomical Union formally accepted 88 modern constellations, with contiguous boundaries that together cover the entire celestial sphere. Any given point in a celestial coordinate system lies in one of the modern constellations; some astronomical naming systems include the constellation where a given celestial object is found to convey its approximate location in the sky. The Flamsteed designation of a star, for example, consists of a number and the genitive form of the constellation name. Other star patterns or groups called asterisms are not constellations per se but are used by observers to navigate the night sky. Examples of bright asterisms include the Pleiades and Hyades within the constellation Taurus or Venus' Mirror in the constellation of Orion.. Some asterisms, like the False Cross, are split between two constellations; the word "constellation" comes from the Late Latin term cōnstellātiō, which can be translated as "set of stars".
The Ancient Greek word for constellation is ἄστρον. A more modern astronomical sense of the term "constellation" is as a recognisable pattern of stars whose appearance is associated with mythological characters or creatures, or earthbound animals, or objects, it can specifically denote the recognized 88 named constellations used today. Colloquial usage does not draw a sharp distinction between "constellations" and smaller "asterisms", yet the modern accepted astronomical constellations employ such a distinction. E.g. the Pleiades and the Hyades are both asterisms, each lies within the boundaries of the constellation of Taurus. Another example is the northern asterism known as the Big Dipper or the Plough, composed of the seven brightest stars within the area of the IAU-defined constellation of Ursa Major; the southern False Cross asterism includes portions of the constellations Carina and Vela and the Summer Triangle.. A constellation, viewed from a particular latitude on Earth, that never sets below the horizon is termed circumpolar.
From the North Pole or South Pole, all constellations south or north of the celestial equator are circumpolar. Depending on the definition, equatorial constellations may include those that lie between declinations 45° north and 45° south, or those that pass through the declination range of the ecliptic or zodiac ranging between 23½° north, the celestial equator, 23½° south. Although stars in constellations appear near each other in the sky, they lie at a variety of distances away from the Earth. Since stars have their own independent motions, all constellations will change over time. After tens to hundreds of thousands of years, familiar outlines will become unrecognizable. Astronomers can predict the past or future constellation outlines by measuring individual stars' common proper motions or cpm by accurate astrometry and their radial velocities by astronomical spectroscopy; the earliest evidence for the humankind's identification of constellations comes from Mesopotamian inscribed stones and clay writing tablets that date back to 3000 BC.
It seems that the bulk of the Mesopotamian constellations were created within a short interval from around 1300 to 1000 BC. Mesopotamian constellations appeared in many of the classical Greek constellations; the oldest Babylonian star catalogues of stars and constellations date back to the beginning in the Middle Bronze Age, most notably the Three Stars Each texts and the MUL. APIN, an expanded and revised version based on more accurate observation from around 1000 BC. However, the numerous Sumerian names in these catalogues suggest that they built on older, but otherwise unattested, Sumerian traditions of the Early Bronze Age; the classical Zodiac is a revision of Neo-Babylonian constellations from the 6th century BC. The Greeks adopted the Babylonian constellations in the 4th century BC. Twenty Ptolemaic constellations are from the Ancient Near East. Another ten have the same stars but different names. Biblical scholar, E. W. Bullinger interpreted some of the creatures mentioned in the books of Ezekiel and Revelation as the middle signs of the four quarters of the Zodiac, with the Lion as Leo, the Bull as Taurus, the Man representing Aquarius and the Eagle standing in for Scorpio.
The biblical Book of Job also
Eagle is the common name for many large birds of prey of the family Accipitridae. Eagles belong to several groups of genera, not all of which are related. Most of the 60 species of eagle are from Africa. Outside this area, just 14 species can be found—2 in North America, 9 in Central and South America, 3 in Australia. Eagles are large, powerfully built birds of prey, with heavy beaks; the smallest eagles, such as the booted eagle, comparable in size to a common buzzard or red-tailed hawk, have longer and more evenly broad wings, more direct, faster flight – despite the reduced size of aerodynamic feathers. Most eagles are larger than any other raptors apart from some vultures; the smallest species of eagle is the South Nicobar serpent eagle, at 40 cm. The largest species are discussed below. Like all birds of prey, eagles have large, hooked beaks for ripping flesh from their prey, muscular legs, powerful talons; the beak is heavier than that of most other birds of prey. Eagles' eyes are powerful.
It is estimated that the martial eagle, whose eye is more than twice as long as a human eye, has a visual acuity 3.0 to 3.6 times that of humans. This acuity enables eagles to spot potential prey from a long distance; this keen eyesight is attributed to their large pupils which ensure minimal diffraction of the incoming light. The female of all known species of eagles is larger than the male. Eagles build their nests, called eyries, in tall trees or on high cliffs. Many species lay two eggs, but the older, larger chick kills its younger sibling once it has hatched; the dominant chick tends to be a female. The parents take no action to stop the killing. Due to the size and power of many eagle species, they are ranked at the top of the food chain as apex predators in the avian world; the type of prey varies by genus. The Haliaeetus and Ichthyophaga eagles prefer to capture fish, though the species in the former capture various animals other water birds, are powerful kleptoparasites of other birds.
The snake and serpent eagles of the genera Circaetus and Spilornis predominantly prey on the great diversity of snakes found in the tropics of Africa and Asia. The eagles of the genus Aquila are the top birds of prey in open habitats, taking any medium-sized vertebrate they can catch. Where Aquila eagles are absent, other eagles, such as the buteonine black-chested buzzard-eagle of South America, may assume the position of top raptorial predator in open areas. Many other eagles, including the species-rich genus Spizaetus, live predominantly in woodlands and forest; these eagles target various arboreal or ground-dwelling mammals and birds, which are unsuspectingly ambushed in such dense, knotty environments. Hunting techniques differ among the species and genera, with some individual eagles having engaged in quite varied techniques based their environment and prey at any given time. Most eagles grab prey without landing and take flight with it, so the prey can be carried to a perch and torn apart.
The bald eagle is noted for having flown with the heaviest load verified to be carried by any flying bird, since one eagle flew with a 6.8 kg mule deer fawn. However, a few eagles may target prey heavier than themselves. Golden and crowned eagles have killed ungulates weighing up to 30 kg and a martial eagle killed a 37 kg duiker, 7–8 times heavier than the preying eagle. Authors on birds David Allen Sibley, Pete Dunne, Clay Sutton described the behavioral difference between hunting eagles and other birds of prey thus: They have at least one singular characteristic, it has been observed. All hawks seem to have this habit, from the smallest kestrel to the largest Ferruginous – but not the Eagles. Among the eagles are some of the largest birds of prey: only the condors and some of the Old World vultures are markedly larger, it is debated which should be considered the largest species of eagle. They could be measured variously in body mass, or wingspan. Different lifestyle needs among various eagles result in variable measurements from species to species.
For example, many forest-dwelling eagles, including the large harpy eagle, have short wingspans, a feature necessary for being able to maneuver in quick, short bursts through densely forested habitats. Eagles in the genus Aquila, though found strictly in open country, are superlative soarers, have long wings for their size; these lists of the top five eagles are based on weight and wingspan, respectively. Unless otherwise noted by reference, the figures listed are the median reported for each measurement in the guide Raptors of the World in which only measurements that could be verified by the authors were listed. Australasian Australia: wedge-tailed eagle, white-bellied sea-eagle, little eagle. New Guinea: Papuan eagle, white-bellied sea-eagle, pygmy eagle. Nearctic: golden eagle, bald eagle. Neotropical: Spizaetus, solitary eagles, harpy eagle, crested eagle, black-chested buzzard-eagle
Johannes Hevelius was a councillor and mayor of Danzig, Kingdom of Poland. As an astronomer, he gained a reputation as "the founder of lunar topography", described ten new constellations, seven of which are still used by astronomers. According to the Polish Academy of Sciences the origin of the name goes back to the surname Hawke, a historical alternative spelling for the English word hawk, which changed into Hawelke or Hawelecke. In Poland he is known as Jan Heweliusz, According to Patrick Moore Hevelius is a Latinised version of the name Hewelcke other versions of the name include Hewel, Hevelke or Hoefel, Höwelcke, Höfelcke. According to Feliks Bentkowski during his early years he signed as Hoefelius, Ludwig Günther-Fürstenwalde reports, next to the usage of the Latinised version, Hevelius' signature as Johannes Höffelius Dantiscanus in 1631 and Hans Höwelcke in 1639. Hevelius' father was his mother Kordula Hecker, they were wealthy brewing merchants of Bohemian origin. As a young boy, Hevelius was sent to Gądecz.
Hevelius brewed the famous Jopen beer, which gave its name to the "Jopengasse"/"Jopejska" Street, after 1945 renamed as Piwna Street, where St. Mary's Church is located. After gymnasium, where he was taught by Peter Crüger, Hevelius in 1630 studied jurisprudence at Leiden travelled in England and France, meeting Pierre Gassendi, Marin Mersenne and Athanasius Kircher. In 1634 he settled in his native town, on 21 March 1635 married Katharine Rebeschke, a neighbour two years younger who owned two adjacent houses; the following year, Hevelius became a member of the beer-brewing guild, which he led from 1643 onwards. Throughout his life, Hevelius took a leading part in municipal administration, becoming town councillor in 1651. In 1641 he built an observatory on the roofs of his three connected houses, equipping it with splendid instruments including a large Keplerian telescope of 46 m focal length, with a wood and wire tube he constructed himself; this may have been the longest "tubed" telescope before the advent of the tubeless aerial telescope.
The observatory was known by the name Sternenburg or "Star Castle". This private observatory was visited by Polish Queen Marie Louise Gonzaga on 29 January 1660; as a subject of the Polish kings, Hevelius enjoyed the patronage of four consecutive kings of Poland, his family was raised to the position of nobility by the King of Poland Jan Kazimierz in 1660, who visited his observatory in 1659. While the noble status was not ratified by the Polish Sejm Hevelius's coat of arms includes the distinctive Polish royal crown; the Polish King John III Sobieski who visited Hevelius numerous times in years 1677–1683 released him from paying taxes connected to brewing and allowed his beer to be sold outside the city limits. In May 1679 the young Englishman Edmond Halley visited him as emissary of the Royal Society, whose fellow Hevelius had been since 1664; the Royal Society considers him one of the first German fellows. Małgorzata Czerniakowska writes that "Jan Heweliusz was the first Pole to be inducted into the Royal Society in London.
This important event took place on 19th March 1664". Hevelius considered himself as being citizen of the Polish world and stated in a letter dated from 9 January 1681 that he was Civis orbis Poloni, qui in honorem patriae suae rei Literariae bono tot labores molestiasque, absit gloria, cum maximo facultatum suarum dispendio perduravit-"citizen of Polish world who, for glory of his country and for the good of science, worked so much, while not boasting much, executed his work with most effort per his abilities" Halley had been instructed by Robert Hooke and John Flamsteed to persuade Hevelius to use telescopes for his measurements, yet Hevelius demonstrated that he could do well with only quadrant and alidade, he is thus considered the last astronomer to do major work without the use of a telescope. Hevelius made observations of sunspots, 1642–1645, devoted four years to charting the lunar surface, discovered the Moon's libration in longitude, published his results in Selenographia, sive Lunae descriptio, a work which entitles him to be called "the founder of lunar topography".
He discovered four comets, in 1652, 1661, 1672 and 1677. These discoveries led to his thesis. A complex halo phenomenon was observed by many in the city on 20 February 1661, was described by Hevelius in his Mercurius in Sole visus Gedani the following year. Katharine, his first wife, died in 1662, a year Hevelius married Elisabeth Koopmann, the young daughter of a merchant family; the couple had four children. Elisabeth supported him, published two of his works after his death, is considered the first female astronomer, his observatory and books were destroyed by fire on 26 September 1679. The catastrophe is described in the preface to his Annus climactericus, he promptly repaired the damage enough to enable him to observe the great comet of December 1680. He named the constellation Sextans in memory of this lost instrument. In late 1683, in commemoration of the victory of Christian forces led by Polish King John III Sobieski at the Battle of Vienna, he invented and named the constellation Scutum Sobiescianum, now called Scutum.
This constellation first occurred publicly in his star atlas Firmamentum Sobi
Lyra is a small constellation. It is one of 48 listed by the 2nd century astronomer Ptolemy, is one of the 88 constellations recognized by the International Astronomical Union. Lyra was represented on star maps as a vulture or an eagle carrying a lyre, hence is sometimes referred to as Vultur Cadens or Aquila Cadens, respectively. Beginning at the north, Lyra is bordered by Draco, Hercules and Cygnus. Lyra is visible from the northern hemisphere from spring through autumn, nearly overhead, in temperate latitudes, during the summer months. From the southern hemisphere, it is visible low in the northern sky during the winter months. Vega, Lyra's brightest star, is one of the brightest stars in the night sky, forms a corner of the famed Summer Triangle asterism. Beta Lyrae is the prototype of a class of stars known as Beta Lyrae variables; these binary stars are so close to each other that they become egg-shaped and material flows from one to the other. Epsilon Lyrae, known informally as the Double Double, is a complex multiple star system.
Lyra hosts the Ring Nebula, the second-discovered and best-known planetary nebula. In Greek mythology, Lyra represents the lyre of Orpheus. Made by Hermes from a tortoise shell, given to Apollo as a bargain, it was said to be the first lyre produced. Orpheus's music was said to be so great that inanimate objects such as trees and rocks could be charmed. Joining Jason and the Argonauts, his music was able to quell the voices of the dangerous Sirens, who sang tempting songs to the Argonauts. At one point, Orpheus married a nymph. While fleeing from an attack by Aristaeus, she stepped on a snake. To reclaim her, Orpheus entered the Underworld. Hades relented and let Orpheus bring Eurydice back, on the condition that he never once look back until outside. Near the end, Orpheus faltered and looked back, causing Eurydice to be left in the Underworld forever. Orpheus spent the rest of his life strumming his lyre while wandering aimlessly through the land, rejecting all marriage offers from women. There are two competing myths relating to the death of Orpheus.
According to Eratosthenes, Orpheus failed to make a necessary sacrifice to Dionysus due to his regard for Apollo as the supreme deity instead. Dionysus sent his followers to rip Orpheus apart. Ovid tells a rather different story, saying that women, in retribution for Orpheus's rejection of marriage offers, ganged up and threw stones and spears. At first, his music charmed them as well, but their numbers and clamor overwhelmed his music and he was hit by the spears. Both myths state that his lyre was placed in the sky by Zeus, Orpheus' bones buried by the muses. Vega and its surrounding stars are treated as a constellation in other cultures; the area corresponding to Lyra was seen by the Arabs as a vulture or an eagle carrying a lyre, either enclosed in its wings, or in its beak. In Wales, Lyra is known as King Arthur's Harp, King David's harp; the Persian Hafiz called it the Lyre of Zurah. It has been called the Manger of Praesepe Salvatoris. In Australian Aboriginal astronomy, Lyra is known by the Boorong people in Victoria as the Malleefowl constellation.
Lyra was worshipped as an animal deity. Lyra is bordered by Vulpecula to the south, Hercules to the east, Draco to the north, Cygnus to the west. Covering 286.5 square degrees, it ranks 52nd of the 88 modern constellations in size. It appears prominently in the northern sky during the Northern Hemisphere's summer, the whole constellation is visible for at least part of the year to observers north of latitude 42°S, its main asterism consists of six stars, 73 stars in total are brighter than magnitude 6.5. The constellation's boundaries, as set by Eugène Delporte in 1930, are defined by a 17-sided polygon. In the equatorial coordinate system, the right ascension coordinates of these borders lie between 18h 14m and 19h 28m, while the declination coordinates are between +25.66° and +47.71°. The International Astronomical Union adopted the three-letter abbreviation "Lyr" for the constellation in 1922. German cartographer Johann Bayer used the Greek letters alpha through nu to label the most prominent stars in the constellation.
Flamsteed observed and labelled two stars each as delta, zeta and nu. He added pi and rho, not using xi and omicron as Bayer used hese letters to denote Cygnus and Hercules on his map; the brightest and far the most well-known star in the constellation is Vega, a main-sequence star of spectral type A0Va. Only 7.7 parsecs distant, is a Delta Scuti variable, varying between magnitudes −0.02 and 0.07 over 0.2 days. On average, it is the second-brightest star of a northern hemisphere and the fifth-brightest star in all, surpassed only by Arcturus, Alpha Centauri and Sirius. Vega was the pole star in the year 12,000 BCE, will again become the pole star around 14,000 CE. Vega is one of the most-magnificent of all stars, has been called "arguably the next most important star in the sky after the Sun". Vega was the first star other than the Sun to be photographed, as well as the first to have a clear spectrum recorded, showing absorption lines for the first time; the star was the first single main-sequence star other than the Sun to be known to emit X-rays, is surrounded by a circumstellar debris disk, similar to the Kuiper Belt.
Vega forms one corner of the famous Summer Triangle asterism. Vega forms one vertex of a much s
The apparent magnitude of an astronomical object is a number, a measure of its brightness as seen by an observer on Earth. The magnitude scale is logarithmic. A difference of 1 in magnitude corresponds to a change in brightness by a factor of 5√100, or about 2.512. The brighter an object appears, the lower its magnitude value, with the brightest astronomical objects having negative apparent magnitudes: for example Sirius at −1.46. The measurement of apparent magnitudes or brightnesses of celestial objects is known as photometry. Apparent magnitudes are used to quantify the brightness of sources at ultraviolet and infrared wavelengths. An apparent magnitude is measured in a specific passband corresponding to some photometric system such as the UBV system. In standard astronomical notation, an apparent magnitude in the V filter band would be denoted either as mV or simply as V, as in "mV = 15" or "V = 15" to describe a 15th-magnitude object; the scale used to indicate magnitude originates in the Hellenistic practice of dividing stars visible to the naked eye into six magnitudes.
The brightest stars in the night sky were said to be of first magnitude, whereas the faintest were of sixth magnitude, the limit of human visual perception. Each grade of magnitude was considered twice the brightness of the following grade, although that ratio was subjective as no photodetectors existed; this rather crude scale for the brightness of stars was popularized by Ptolemy in his Almagest and is believed to have originated with Hipparchus. In 1856, Norman Robert Pogson formalized the system by defining a first magnitude star as a star, 100 times as bright as a sixth-magnitude star, thereby establishing the logarithmic scale still in use today; this implies that a star of magnitude m is about 2.512 times as bright as a star of magnitude m + 1. This figure, the fifth root of 100, became known as Pogson's Ratio; the zero point of Pogson's scale was defined by assigning Polaris a magnitude of 2. Astronomers discovered that Polaris is variable, so they switched to Vega as the standard reference star, assigning the brightness of Vega as the definition of zero magnitude at any specified wavelength.
Apart from small corrections, the brightness of Vega still serves as the definition of zero magnitude for visible and near infrared wavelengths, where its spectral energy distribution approximates that of a black body for a temperature of 11000 K. However, with the advent of infrared astronomy it was revealed that Vega's radiation includes an Infrared excess due to a circumstellar disk consisting of dust at warm temperatures. At shorter wavelengths, there is negligible emission from dust at these temperatures. However, in order to properly extend the magnitude scale further into the infrared, this peculiarity of Vega should not affect the definition of the magnitude scale. Therefore, the magnitude scale was extrapolated to all wavelengths on the basis of the black-body radiation curve for an ideal stellar surface at 11000 K uncontaminated by circumstellar radiation. On this basis the spectral irradiance for the zero magnitude point, as a function of wavelength, can be computed. Small deviations are specified between systems using measurement apparatuses developed independently so that data obtained by different astronomers can be properly compared, but of greater practical importance is the definition of magnitude not at a single wavelength but applying to the response of standard spectral filters used in photometry over various wavelength bands.
With the modern magnitude systems, brightness over a wide range is specified according to the logarithmic definition detailed below, using this zero reference. In practice such apparent magnitudes do not exceed 30; the brightness of Vega is exceeded by four stars in the night sky at visible wavelengths as well as the bright planets Venus and Jupiter, these must be described by negative magnitudes. For example, the brightest star of the celestial sphere, has an apparent magnitude of −1.4 in the visible. Negative magnitudes for other bright astronomical objects can be found in the table below. Astronomers have developed other photometric zeropoint systems as alternatives to the Vega system; the most used is the AB magnitude system, in which photometric zeropoints are based on a hypothetical reference spectrum having constant flux per unit frequency interval, rather than using a stellar spectrum or blackbody curve as the reference. The AB magnitude zeropoint is defined such that an object's AB and Vega-based magnitudes will be equal in the V filter band.
As the amount of light received by a telescope is reduced by transmission through the Earth's atmosphere, any measurement of apparent magnitude is corrected for what it would have been as seen from above the atmosphere. The dimmer an object appears, the higher the numerical value given to its apparent magnitude, with a difference of 5 magnitudes corresponding to a brightness factor of 100. Therefore, the apparent magnitude m, in the spectral band x, would be given by m x = − 5 log 100 , more expressed in terms of common logarithms as m x