"or good binoculars, the planets appear as discs demonstrating finite size, and it is possible to observe orbiting moons which cast shadows onto the host planet's surface. Venus is the most prominent planet, often called the ""morning star"" or ""evening star"" because it is brighter than the stars and often the only ""star"" visible near sunrise or sunset, depending on its location in its orbit. Mercury, Mars, Jupiter and Saturn are also visible to the naked eye. Earth's Moon is a grey disc in the sky with cratering visible to the naked eye. It spans, depending on its exact location,"
"the star when rising left the viewer with the impression that it was red. To the naked eye, it often appears to be flashing with red, white and blue hues when near the horizon. With an apparent magnitude of −1.46, Sirius is the brightest star system in the night sky, almost twice as bright as the second brightest star, Canopus. From Earth, Sirius always appears dimmer than Jupiter and Venus, as well as Mercury and Mars at certain times. Sirius is visible from almost everywhere on Earth, except latitudes north of 73° N, and it does not rise very high"
"bright stars. These include Sirius (Alpha Canis Majoris), the brightest star in the night sky, as well as three other stars above magnitude 2.0. Furthermore, two other stars are thought to have previously outshone all others in the night sky—Adhara (Epsilon Canis Majoris) shone at -3.99 around 4.7 million years ago, and Mirzam (Beta Canis Majoris) peaked at −3.65 around 4.42 million years ago. Another, NR Canis Majoris, will be brightest at magnitude −0.88 in about 2.87 million years' time. The German cartographer Johann Bayer used the Greek letters Alpha through Omicron to label the most prominent stars in the"
"from extreme polar locations. Mars is at its brightest when it is in opposition, which occurs approximately every twenty-five months. Jupiter and Saturn are the largest of the five planets, but are farther from the Sun, and therefore receive less sunlight. Nonetheless, Jupiter is often the next brightest object in the sky after Venus. Saturn's luminosity is often enhanced by its rings, which reflect light to varying degrees, depending on their inclination to the ecliptic; however, the rings themselves are not visible to the naked eye from the Earth. Uranus and sometimes the asteroid Vesta are in principle visible to"
"Venus is the brightest object in the sky after the Sun and the Moon, outshining the planets Jupiter and Saturn but, while these rise high in the sky, Venus never does. This may lie behind myths about deities associated with the morning star proudly striving for the highest place among the gods and being cast down. In Greek mythology, Hesiod calls Phosphorus a son of Astraeus and Eos, but other say of Cephalus and Eos, or of Atlas. The Latin poet Ovid, speaking of Phosphorus and Hesperus (the Evening Star, the evening appearance of the planet Venus) as identical, makes"
"the most luminous objects in the known universe. The brightest quasar in the sky is 3C 273 in the constellation of Virgo. It has an average apparent magnitude of 12.8 (bright enough to be seen through a medium-size amateur telescope), but it has an absolute magnitude of −26.7. From a distance of about 33 light-years, this object would shine in the sky about as brightly as our sun. This quasar's luminosity is, therefore, about 4 trillion (4 × 10) times that of the Sun, or about 100 times that of the total light of giant galaxies like the Milky Way."
"Sirius Sirius (, a latinisation of Greek , ""Seirios"", .""glowing"" or ""scorching"") is a binary star and the brightest point of light in the night sky. With a visual apparent magnitude of −1.46, it is almost twice as bright as Canopus, the next brightest star. The system has the Bayer designation α (Alpha) Canis Majoris. The binary system consists of a main-sequence star of spectral type A0 or A1, termed Sirius A, and a faint white dwarf companion of spectral type DA2, designated Sirius B. The distance between the two varies between 8.2 and 31.5 astronomical units as they orbit"
"Sirius in fiction The planetary systems of stars other than the Sun and the Solar System are a staple element in much science fiction. Sirius, a double star system with the binary designation Sirius AB, is the brightest stellar object in the night sky. Its component stars are Sirius A (the primary—twice as massive and 25 times more luminous than the Sun) and Sirius B (the secondary—a faint white dwarf). The distance separating Sirius A from its companion varies between 8.1 and 31.5 AU, reflecting the eccentricity of their mutual orbits. The system contains no known extrasolar planets (see ""Traveller"""
"Historical brightest stars The Solar System and all of the visible stars are in different orbits about the core of the Milky Way galaxy. Thus, their relative positions change over time, and for the nearer stars this movement can be measured. As a star moves toward or away from us, its apparent brightness changes. Sirius is currently the brightest star in Earth's night sky, but it has not always been so. Canopus has persistently been the brightest star over the ages; other stars appear brighter only during relatively temporary periods, during which they are passing the Solar System at a"
"chance that the Solar System could be ejected from the Milky Way or join the Andromeda Galaxy. The Andromeda Galaxy is bright enough to be seen with the naked eye, even with some light pollution. Andromeda is best seen during autumn nights in the Northern Hemisphere, when from mid-latitudes the galaxy reaches zenith (its highest point at midnight) so can be seen almost all night. From the Southern Hemisphere, it is most visible at the same months, that is in spring, and away from our equator does not reach a high altitude over the northern horizon, making it difficult to"
"ISS is the brightest artificial object in the sky, excluding flares, with an approximate maximum magnitude of −4 when overhead (similar to Venus). The ISS, like many satellites including the Iridium constellation, can also produce flares of up to 8 or 16 times the brightness of Venus as sunlight glints off reflective surfaces. The ISS is also visible in broad daylight, albeit with a great deal more difficulty. Tools are provided by a number of websites such as Heavens-Above (see ""Live viewing"" below) as well as smartphone applications that use orbital data and the observer's longitude and latitude to indicate"
"that is the second brightest star in the night sky at magnitude −0.72, 313 light-years from Earth. Alpha Carinae, as Canopus is formally designated, is a variable star that varies by approximately 0.1 magnitudes. Its traditional name comes from the mythological Canopus, who was a navigator for Menelaus, king of Sparta. There are several other stars above magnitude 3 in Carina. Beta Carinae, traditionally called Miaplacidus, is a blue-white hued star of magnitude 1.7, 111 light-years from Earth. Epsilon Carinae is an orange-hued giant star similarly bright to Miaplacidus at magnitude 1.9; it is 630 light-years from Earth. Another fairly"
"Canopus Canopus (), also designated Alpha Carinae (α Carinae, abbreviated Alpha Car, α Car), is the brightest star in the southern constellation of Carina, and the second-brightest star in the night sky, after Sirius. Canopus's visual magnitude is −0.74, and it has an absolute magnitude of −5.71. Canopus is a bright giant of spectral type A9, so it is essentially white when seen with the naked eye. It is located in the far southern sky, at a year 2000 declination of and a right ascension of . Its name is generally considered to originate from the mythological Canopus, who was"
"Deneb Deneb (), also designated α Cygni (Latinised alpha Cygni, abbreviated Alpha Cyg, α Cyg), is the brightest star in the constellation of Cygnus, the swan. It is one of the vertices of the asterism known as the Summer Triangle and forms the 'head' of the Northern Cross. It is the 19th brightest star in the night sky, with an apparent magnitude of 1.25. A blue-white supergiant, Deneb is also one of the most luminous stars. However, its exact distance (and hence luminosity) has been difficult to calculate; it is estimated to be somewhere between 55,000 and 196,000 times as"
"Betelgeuse Betelgeuse, also designated Alpha Orionis (α Orionis, abbreviated Alpha Ori, α Ori), is on average the ninth-brightest star in the night sky and second-brightest in the constellation of Orion. It is distinctly reddish, and is a semiregular variable star whose apparent magnitude varies between 0.0 and 1.3, the widest range of any first-magnitude star. Betelgeuse is one of three stars that make up the asterism of the Winter Triangle, and it marks the center of the Winter Hexagon. If the human eye could view all wavelengths of radiation, Betelgeuse would be the brightest star in the night sky. Classified"
"it doesn't include Gliese 710 which in about 1.35 million years time is expected to be close enough to have a magnitude of -2.7. Historical brightest stars The Solar System and all of the visible stars are in different orbits about the core of the Milky Way galaxy. Thus, their relative positions change over time, and for the nearer stars this movement can be measured. As a star moves toward or away from us, its apparent brightness changes. Sirius is currently the brightest star in Earth's night sky, but it has not always been so. Canopus has persistently been the"
"possible investigations into the habitability and possible discovery of life on Saturn's moons Titan and Enceladus. Saturn is the most distant of the five planets easily visible to the naked eye from Earth, the other four being Mercury, Venus, Mars and Jupiter. (Uranus and occasionally 4 Vesta are visible to the naked eye in dark skies.) Saturn appears to the naked eye in the night sky as a bright, yellowish point of light. The mean apparent magnitude of Saturn is 0.46 with a standard deviation of 0.34. Most of the magnitude variation is due to the inclination of the ring"
"13 Canis Majoris—as Kappa and Kappa respectively, but subsequent cartographers such as Francis Baily and John Bevis dropped the fainter former star, leaving Kappa as the sole Kappa. Flamsteed's listing of Nu, Nu, Nu, Xi, Xi, Omicron and Omicron have all remained in use. Sirius is the brightest star in the night sky at apparent magnitude −1.46 and one of the closest stars to Earth at a distance of 8.6 light-years. Its name comes from the Greek word for ""scorching"" or ""searing"". Sirius is also a binary star; its companion Sirius B is a white dwarf with a magnitude of"
"Rigel Rigel (), also designated Beta Orionis (β Orionis, abbreviated Beta Ori, β Ori), is generally the seventh-brightest star in the night sky and the brightest in the constellation of Orion—though occasionally it is outshone within the constellation by the variable star Betelgeuse. With an apparent magnitude of 0.13, it is a luminous object some 863 light-years distant from Earth. Rigel as seen from Earth is actually a multiple star system of three to five stars, the primary star (Rigel A) being a blue-white supergiant which is estimated to be anywhere from 120,000 to 279,000 times as luminous as the"
"Regulus Regulus, also designated Alpha Leonis (α Leonis, abbreviated Alpha Leo, α Leo), is the brightest star in the constellation of Leo and one of the brightest stars in the night sky, lying approximately 79 light years from the Sun. Regulus is a multiple star system composed of four stars that are organized into two pairs. The spectroscopic binary Regulus A consists of a blue-white main-sequence star and its companion, which has not yet been directly observed, but is probably a white dwarf. Located farther away are Regulus B, C, and D, which are dim main-sequence stars. ""α Leonis"" (Latinized"
"Beta Cancri Beta Cancri (β Cancri, abbreviated Beta Cnc, β Cnc), also named Tarf, is the brightest star in the zodiacal constellation of Cancer. It has an apparent visual magnitude of +3.5 and an absolute magnitude of −1.2. Based on parallax measurements obtained during the Hipparcos mission, it is approximately 290 light-years distant from the Sun. An exoplanet, designated Beta Cancri b, is believed to be orbiting the star. Beta Cancri has a companion listed and together they are designated WDS J08165+0911. As the primary, Beta Cancri bears the designation WDS J08165+0911A. The companion is designated WDS J08165+0911B. ""β Cancri"""
"Achernar Achernar is the name of the primary (or 'A') component of the binary system designated Alpha Eridani (α Eridani, abbreviated Alpha Eri, α Eri), which is the brightest 'star' or point of light in, and lying at the southern tip of, the constellation of Eridanus, and the tenth-brightest in the night sky. The two components are designated Alpha Eridani A (the primary) and B (the secondary, also known informally as Achernar B). As determined by the Hipparcos astrometry satellite, it is approximately from the Sun. Of the ten apparent brightest stars in the night-time sky, Alpha Eridani is the"
"is the third-brightest star in the constellation Cygnus, is actually a close binary itself. Also in the Cygnus constellation is Cygnus X-1, an X-ray source considered to be a black hole. It is a high-mass X-ray binary, with the optical counterpart being a variable star. Sirius is another binary and the brightest star in the night time sky, with a visual apparent magnitude of −1.46. It is located in the constellation Canis Major. In 1844 Friedrich Bessel deduced that Sirius was a binary. In 1862 Alvan Graham Clark discovered the companion (Sirius B; the visible star is Sirius A). In"
"transit. Mercury is technically brightest as seen from Earth when it is at a full phase. Although Mercury is farthest from Earth when it is full, the greater illuminated area that is visible and the opposition brightness surge more than compensates for the distance. The opposite is true for Venus, which appears brightest when it is a crescent, because it is much closer to Earth than when gibbous. Nonetheless, the brightest (full phase) appearance of Mercury is an essentially impossible time for practical observation, because of the extreme proximity of the Sun. Mercury is best observed at the first and"
"Orion (constellation) Orion is a prominent constellation located on the celestial equator and visible throughout the world. It is one of the most conspicuous and recognizable constellations in the night sky. It was named after Orion, a hunter in Greek mythology. Its brightest stars are Rigel (Beta Orionis) and Betelgeuse (Alpha Orionis), a blue-white and a red supergiant, respectively. The earliest depiction that has been linked to the constellation of Orion is a prehistoric (Aurignacian) mammoth ivory carving found in a cave in the Ach valley in West Germany in 1979. Archaeologists have estimated it to have been fashioned approximately"
"some of the brightest stars in the sky. Rigel, the brightest star in the constellation Orion is a typical blue-white supergiant; Deneb is the brightest star in Cygnus, a white supergiant; Delta Cephei is the famous prototype Cepheid variable, a yellow supergiant; and Betelgeuse, Antares and UY Scuti are red supergiants. μ Cephei is one of the reddest stars visible to the naked eye and one of the largest in the galaxy. Rho Cassiopeiae, a variable, yellow hypergiant, is one of the most luminous naked-eye stars. Supergiant star Supergiants are among the most massive and most luminous stars. Supergiant stars"
"eye: Mercury, Venus, Mars, Jupiter, and Saturn. Under typical dark sky conditions Uranus (magnitude +5.8) can be seen as well with averted vision, as can the asteroid Vesta at its brighter oppositions. The Sun and the Moon—the remaining noticeable naked-eye objects of the solar system—are sometimes added to make seven ""planets."" During daylight only the Moon and Sun are obvious naked eye objects, but in many cases Venus can be spotted in daylight and in rarer cases Jupiter. Close to sunset and sunrise bright stars like Sirius or even Canopus can be spotted with the naked eye as long as"
"Earth's sky, among other reasons, many telescopes are put outside of the Earth's atmosphere, where not only light pollution, but also atmospheric distortion and obscuration are minimized. The most commonly observed objects tend to be ones that do not require a telescope to view, such as the Moon, meteors, planets, constellations, and stars. The Moon is a very commonly observed astronomical object, especially by amateur astronomers and skygazers. This is due to several reasons: the Moon is the brightest object in the night sky, the Moon is the largest object in the night sky, and the Moon has long been"
"3C 454.3 3C 454.3 is a blazar (a type of quasar with a jet oriented toward Earth) located away from the galactic plane. It is one of the brightest gamma ray sources in the sky, and is the most luminous astronomical object ever observed, with a maximum absolute magnitude of -31.4. It has the brightest blazar gamma ray flare recorded, twice as bright as the Vela Pulsar in the Milky Way galaxy. It also flares at radio and visible wavelengths – in red light, the blazar brightened by more than 2.5 times to magnitude 13.7 – and it is very"
"of 26 from Andromeda, 9 from Lacerta, 6 from Cepheus, 5 from Pegasus, and 3 from Cassiopeia. The three brightest stars—all of magnitude 4—that lay within its borders are Omicron, Lambda, and Kappa Andromedae. With an apparent magnitude of 3.62, Omicron Andromedae is a multiple star system, the brightest star of which is a blue-white subgiant of spectral type B6 IIIpe and its visible companion a white star of spectral type A2. Each appears to have a close companion, making it a quadruple system. It is approximately 690 light-years from Earth. Lambda Andromedae is a yellow subgiant star of spectral"
"most obvious deep-sky object is the naked-eye Andromeda Galaxy (M31, also called the Great Galaxy of Andromeda), the closest spiral galaxy to the Milky Way and one of the brightest Messier objects. Several fainter galaxies, including M31's companions M110 and M32, as well as the more distant NGC 891, lie within Andromeda. The Blue Snowball Nebula, a planetary nebula, is visible in a telescope as a blue circular object. In Chinese astronomy, the stars that make up Andromeda were members of four different constellations that had astrological and mythological significance; a constellation related to Andromeda also exists in Hindu mythology."
"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 very wide range is specified according to the logarithmic definition detailed below, using this zero reference. In practice such apparent magnitudes do not exceed 30 (for detectable measurements). The brightness of Vega is exceeded by four stars in the night sky at visible wavelengths (and more at infrared wavelengths) as well as the bright planets Venus, Mars, and Jupiter, and these must be described by ""negative"" magnitudes. For example, Sirius, the brightest star of the"
"but very prominent when viewed from rural areas when the Moon is below the horizon. Maps of artificial night sky brightness show that more than one-third of Earth's population cannot see the Milky Way from their homes due to light pollution. As viewed from Earth, the visible region of the Milky Way's galactic plane occupies an area of the sky that includes 30 constellations. The Galactic Center lies in the direction of Sagittarius, where the Milky Way is brightest. From Sagittarius, the hazy band of white light appears to pass around to the galactic anticenter in Auriga. The band then"