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Galactic Anticenter
The galactic anticenter is a direction in space directly opposite to the Galactic Center, as viewed from Earth. This direction corresponds to a point on the celestial sphere. From the perspective of an observer on Earth, the galactic anticenter is located in the constellation Auriga, and the Crab nebula and the bright star Beta Tauri (Elnath) appear nearest this point. For binocular and telescope observers in dark sky locations, the magnitude 8.5 star HIP 27180 appears closest to this point. Location In terms of the galactic coordinate system, the Galactic Center (in Sagittarius) corresponds to a longitude of 0°, while the anticenter is located exactly at 180°. In the equatorial coordinate system, the anticenter is found at roughly RA 05h 46m, dec +28° 56'. See also *Anticenter shell *Galactic Center References Anticenter Anticenter {{Spiral-galaxy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galactic Coordinate System
The galactic coordinate system is a celestial coordinate system in spherical coordinates, with the Sun as its center, the primary direction aligned with the approximate center of the Milky Way Galaxy, and the fundamental plane parallel to an approximation of the galactic plane but offset to its north. It uses the right-handed convention, meaning that coordinates are positive toward the north and toward the east in the fundamental plane. Spherical coordinates Galactic longitude Longitude (symbol ) measures the angular distance of an object eastward along the galactic equator from the Galactic Center. Analogous to terrestrial longitude, galactic longitude is usually measured in degrees (°). Galactic latitude Latitude (symbol ) measures the angle of an object northward of the galactic equator (or midplane) as viewed from Earth. Analogous to terrestrial latitude, galactic latitude is usually measured in degrees (°). Definition The first galactic coordinate system was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galactic Center
The Galactic Center or Galactic Centre is the rotational center, the barycenter, of the Milky Way galaxy. Its central massive object is a supermassive black hole of about 4 million solar masses, which is called Sagittarius A*, a compact radio source which is almost exactly at the galactic rotational center. The Galactic Center is approximately away from Earth in the direction of the constellations Sagittarius, Ophiuchus, and Scorpius, where the Milky Way appears brightest, visually close to the Butterfly Cluster (M6) or the star Shaula, south to the Pipe Nebula. There are around 10 million stars within one parsec of the Galactic Center, dominated by red giants, with a significant population of massive supergiants and Wolf–Rayet stars from star formation in the region around 1 million years ago. The core stars are a small part within the much wider galactic bulge. Discovery Because of interstellar dust along the line of sight, the Galactic Center cannot be studied at v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anticenter Shell
The anticenter shell or anticenter superbubble is a region near the anticenter of the Milky Way Galaxy that emits 21 cm radiation. It is located at , or l = 197°, b = +2° in galactic coordinates, near the border of the constellations Gemini and Orion. It is a supershell (a very large superbubble) within our galaxy that is spherical in shape and features jets of gas. Discovered in 1970, this galactic object has subsequently been variously classified by researchers as a spiral arm of the Milky Way in 1972, a nearby tidally-stripped dwarf galaxy in 1975, and a high-velocity cloud in 1979. The name Snickers for the anticenter shell arose from the description in 1975 by Christian Simonson, a University of Maryland astronomer who believed it to be a small "peanut" of a galaxy just outside the Milky Way. Simonson's colleagues coined the name ''Snickers'' (in reference to the American chocolate bars ''Milky Way'' and ''Snickers'') due to its proximity to the Milky Way. Less popu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. Declination's angle is measured north or south of the celestial equator, along the hour circle passing through the point in question. The root of the word ''declination'' (Latin, ''declinatio'') means "a bending away" or "a bending down". It comes from the same root as the words ''incline'' ("bend foward") and ''recline'' ("bend backward"). In some 18th and 19th century astronomical texts, declination is given as ''North Pole Distance'' (N.P.D.), which is equivalent to 90 – (declination). For instance an object marked as declination −5 would have an N.P.D. of 95, and a declination of −90 (the south celestial pole) would have an N.P.D. of 180. Explanation Declination in astronomy is comparable to geographic latitude, projected onto the celestial sphere, and right ascension is like ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 March equinox to the (hour circle of the) point in question above the earth. When paired with declination, these astronomical coordinates specify the location of a point on the celestial sphere in the equatorial coordinate system. An old term, ''right ascension'' ( la, ascensio recta), "''Ascensio recta'' Solis, stellæ, aut alterius cujusdam signi, est gradus æquatorus cum quo simul exoritur in sphæra recta"; roughly translated, "''Right ascension'' of the Sun, stars, or any other sign, is the degree of the equator that rises together in a right sphere" refers to the ''ascension'', or the point on the celestial equator that rises with any celestial object as seen from Earth's equator, where the celestial equator intersects the horizon at a right angle. It contrasts with ''oblique ascension'', the point on the celestial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equatorial Coordinate System
The equatorial coordinate system is a celestial coordinate system widely used to specify the positions of celestial objects. It may be implemented in spherical or rectangular coordinates, both defined by an origin at the centre of Earth, a fundamental plane consisting of the projection of Earth's equator onto the celestial sphere (forming the celestial equator), a primary direction towards the vernal equinox, and a right-handed convention. The origin at the centre of Earth means the coordinates are ''geocentric'', that is, as seen from the centre of Earth as if it were transparent. The fundamental plane and the primary direction mean that the coordinate system, while aligned with Earth's equator and pole, does not rotate with the Earth, but remains relatively fixed against the background stars. A right-handed convention means that coordinates increase northward from and eastward around the fundamental plane. Primary direction This description of the orientation of the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagittarius (constellation)
Sagittarius is one of the constellations of the zodiac and is located in the Southern celestial hemisphere. It is one of the 48 constellations listed by the 2nd-century astronomer Ptolemy and remains one of the 88 modern constellations. Its old astronomical symbol is (♐︎). Its name is Latin for "archer". Sagittarius is commonly represented as a centaur pulling back a bow. It lies between Scorpius and Ophiuchus to the west and Capricornus and Microscopium to the east. The center of the Milky Way lies in the westernmost part of Sagittarius (see Sagittarius A). Visualizations As seen from the northern hemisphere, the constellation's brighter stars form an easily recognizable asterism known as "the Teapot". The stars δ Sgr (Kaus Media), ε Sgr (Kaus Australis), ζ Sgr (Ascella), and φ Sgr form the body of the pot; λ Sgr (Kaus Borealis) is the point of the lid; γ2 Sgr (Alnasl) is the tip of the spout; and σ Sgr (Nunki) and τ Sgr the handle. These same sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hipparcos
''Hipparcos'' was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions of celestial objects on the sky. This permitted the first high-precision measurements of the intrinsic brightnesses (compared to the less precise apparent brightness), proper motions, and parallaxes of stars, enabling better calculations of their distance and tangential velocity. When combined with radial velocity measurements from spectroscopy, astrophysicists were able to finally measure all six quantities needed to determine the motion of stars. The resulting ''Hipparcos Catalogue'', a high-precision catalogue of more than 118,200 stars, was published in 1997. The lower-precision ''Tycho Catalogue'' of more than a million stars was published at the same time, while the enhanced Tycho-2 Catalogue of 2.5 million stars was published in 2000. ''Hipparcos' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auriga
AURIGA (''Antenna Ultracriogenica Risonante per l'Indagine Gravitazionale Astronomica'') is an ultracryogenic resonant bar gravitational wave detector in Italy. It is at the Laboratori Nazionali di Legnaro of the Istituto Nazionale di Fisica Nucleare, near Padova. It is being used for research into gravitational waves and quantum gravity. When the oscillator gets hit with a burst of gravitational waves, it will excite the oscillator and it will vibrate for a time span longer than the duration of the gravitational wave burst. This allows for the extraction of the signal from the detector. See also * LIGO * Weber bar Weber (, or ; German: ) is a surname of German origin, derived from the noun meaning " weaver". In some cases, following migration to English-speaking countries, it has been anglicised to the English surname 'Webber' or even 'Weaver'. Notable pe ... References Astronomical observatories in Italy Gravitational-wave telescopes {{observatory-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Pollution
Light pollution is the presence of unwanted, inappropriate, or excessive use of artificial Visible spectrum, lighting. In a descriptive sense, the term ''light pollution'' refers to the effects of any poorly implemented lighting, during the day or night. Light pollution can be understood not only as a phenomenon resulting from a specific source or kind of pollution, but also as a contributor to the wider, collective impact of various sources of pollution. Although this type of pollution can exist throughout the day, its effects are magnified during the night with the contrast of darkness. It has been estimated that 83 percent of the world's people live under light-polluted skies and that 23 percent of the world's land area is affected by skyglow. The area affected by artificial illumination continues to increase. A major side-effect of urbanization, light pollution is blamed for compromising health, disrupting ecosystems, and spoiling aesthetic environments. Globally, it has incr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Tauri
Beta Tauri is the second-brightest star in the constellation of Taurus (constellation), Taurus. It has the official name Elnath; ''Beta Tauri'' is the current Bayer designation, which is Latinisation of names, Latinised from β Tauri and abbreviated Beta Tau or β Tau. The original designation of Gamma Aurigae is now rarely used. It is a chemically peculiar star, chemically peculiar B7 giant star, 134 light years away from the Sun with an apparent magnitude of 1.65. Nomenclature This star has two Bayer designations: β Tauri (Latinised to Beta Tauri) and γ Aurigae (Latinised to Gamma Aurigae). Ptolemy considered the star to be shared by Auriga (constellation), Auriga, and Johann Bayer assigned it a designation in both constellations. When the modern constellation boundaries were fixed in 1930, the designation γ Aurigae largely dropped from use. The traditional name ''Elnath'', variously ''El Nath'' or ''Alnath'', comes from the Arabic word النطح ''an-naţħ'', mean ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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