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Normae Congregationis
Norma is a small constellation in the Southern Celestial Hemisphere between Ara and Lupus, one of twelve drawn up in the 18th century by French astronomer Nicolas-Louis de Lacaille and one of several depicting scientific instruments. Its name is Latin for normal, referring to a right angle, and is variously considered to represent a rule, a carpenter's square, a set square or a level. It remains one of the 88 modern constellations. Four of Norma's brighter stars—Gamma, Delta, Epsilon and Eta—make up a square in the field of faint stars. Gamma2 Normae is the brightest star with an apparent magnitude of 4.0. Mu Normae is one of the most luminous stars known, with a luminosity between a quarter million and one million times that of the Sun. Four star systems are known to harbour planets. The Milky Way, particularly the Norma Arm of the galaxy, passes through Norma, and the constellation contains eight open clusters visible to observers with binoculars. The constella ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carpenter's Square
The steel square is a tool used in carpentry. Carpenters use various tools to lay out structures that are square (that is, built at accurately measured right angles), many of which are made of steel, but the name ''steel square'' refers to a specific long-armed square that has additional uses for measurement, especially of various angles. It consists of a long, wider arm and a shorter, narrower arm, which meet at an angle of 90 degrees (a right angle). Today the steel square is more commonly referred to as the framing square or carpenter's square, and such squares are no longer invariably made of steel (as they were many decades ago); they can also be made of aluminum or polymers, which are light and resistant to rust. The longer wider arm is wide, and is called the body; the shorter narrower arm, is wide, and is called the tongue. The square has many uses, including laying out common rafters, hip rafters and stairs. It has a diagonal scale, board foot scale and an octagonal sca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
T-square
A T-square is a technical drawing instrument used by draftsmen primarily as a guide for drawing horizontal lines on a drafting table. The instrument is named after its resemblance to the letter T, with a long shaft called the "blade" and a short shaft called the "stock" or "head". T-squares are available in a range of sizes, with common lengths being , , , and . In addition to drawing horizontal lines, a T-square can be used with a set square to draw vertical or diagonal lines. The T-square usually has a transparent edge made of plastic which should be free of nicks and cracks in order to provide smooth, straight lines. T-squares are also used in various industries, such as construction. For example, drywall T-squares are typically made of aluminum and have a tongue, allowing them to be used for measuring and cutting drywall. In woodworking, higher-end table saws often have T-square fence A fence is a structure that encloses an area, typically outdoors, and is usual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galaxy Cluster
A galaxy cluster, or a cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity, with typical masses ranging from 1014 to 1015 solar masses. Clusters consist of galaxies, heated gas, and dark matter. They are the second-largest known gravitationally bound structures in the universe after superclusters. They were believed to be the largest known structures in the universe until the 1980s, when superclusters were discovered. Small aggregates of galaxies are referred to as galaxy groups rather than clusters of galaxies. Together, galaxy groups and clusters form superclusters. Basic properties Galaxy clusters typically have the following properties: * They contain 100 to 1,000 galaxies, hot X-ray emitting gas and large amounts of dark matter. Details are described in the "Composition" section. * They have total masses of 1014 to 1015 solar masses. * They typically have diameters from 1 to 5 Mpc ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norma Cluster
The Norma Cluster (ACO 3627 or Abell 3627) is a rich cluster of galaxies located near the center of the Great Attractor; it is about distant. Although it is both nearby and bright, it is difficult to observe because it is located in the Zone of Avoidance, a region near the plane of the Milky Way. Consequently, the cluster is severely obscured by interstellar dust at optical wavelengths. Its mass is estimated to be on the order of 1015 solar masses. ESO 137-001, an example of a jellyfish galaxy, is located in Abell 3627. Gallery File:New Hubble image of spiral galaxy ESO 137-001.jpg, ESO 137-001 located in the Norma cluster File:A busy patch of the Great Attractor (8386658810).jpg, alt=, ESO 137-2 located in the Norma cluster See also * List of galaxy groups and clusters * Coma Cluster * Eridanus Cluster * Fornax Cluster * Virgo Cluster * X-ray astronomy References External links ESO Press Photos 46a-j/99* NASA The National Aeronautics and Space Administr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open Cluster
An open cluster is a type of star cluster made of tens to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and many more are thought to exist. Each one is loosely bound by mutual gravity, gravitational attraction and becomes disrupted by close encounters with other clusters and clouds of gas as they orbit the Galactic Center. This can result in a loss of cluster members through internal close encounters and a dispersion into the main body of the galaxy. Open clusters generally survive for a few hundred million years, with the most massive ones surviving for a few billion years. In contrast, the more massive globular clusters of stars exert a stronger gravitational attraction on their members, and can survive for longer. Open clusters have been found only in spiral galaxy, spiral and irregular galaxy, irregular galaxies, in which active star formatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norma Arm
The Norma Arm is a minor spiral arm of the Milky Way extending from and around its central hub region. The inner portion of the Arm is called the ''Norma Arm'' in narrow meaning. The outer end of it is identified either with the Cygnus Arm (not to be confused with local and minor Orion-Cygnus Arm), which lies outside the Perseus Arm, or the Outer Arm, which is located farther away from the center of the Galaxy than the Cygnus Arm. The Norma Arm begins from the Galactic Center, and extends outward to a radius of . It is named for the Norma constellation, through which the Arm as seen from Earth passes. Like many other galaxies of similar type, the Milky Way consists of a large mass of stars shaped into the form of a relatively flat disc by gravity. The disc is rotating, with the dense central body of stars moving at greater speeds than those toward the rim of the disc. As a result, the pattern of stars within the Galaxy as viewed from directly above or below the disc has formed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milky Way
The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galaxy, which are so far away that they cannot be individually distinguished by the naked eye. The Milky Way is a barred spiral galaxy with a Galaxy#Isophotal diameter, D25 isophotal diameter estimated at , but only about 1,000 light-years thick at the spiral arms (more at the bulge). Recent simulations suggest that a dark matter area, also containing some visible stars, may extend up to a diameter of almost 2 million light-years (613 kpc). The Milky Way has several List of Milky Way's satellite galaxies, satellite galaxies and is part of the Local Group of galaxies, forming part of the Virgo Supercluster which is itself a component of the Laniakea Supercluster. It is estimated to contain 100–400 billion stars and at least that number of pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luminosity
Luminosity is an absolute measure of radiated electromagnetic radiation, electromagnetic energy per unit time, and is synonymous with the radiant power emitted by a light-emitting object. In astronomy, luminosity is the total amount of electromagnetic energy emitted per unit of time by a star, galaxy, or other astronomical object, astronomical objects. In SI units, luminosity is measured in joules per second, or watts. In astronomy, values for luminosity are often given in the terms of the Solar luminosity, luminosity of the Sun, ''L''⊙. Luminosity can also be given in terms of the astronomical Magnitude (astronomy), magnitude system: the Absolute magnitude#Bolometric magnitude, absolute bolometric magnitude (''M''bol) of an object is a logarithmic measure of its total energy emission rate, while absolute magnitude is a logarithmic measure of the luminosity within some specific wavelength range or Passband, filter band. In contrast, the term ''brightness'' in astronomy is gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mu Normae
μ Normae, Latinised as Mu Normae, is a blue supergiant star of spectral type O9.7 Iab, located in the constellation of Norma. It shines as bright as 339,000 Suns and weighs 40 solar masses. It varies in visual magnitude between 4.87 and 4.98, and is suspected of being an Alpha Cygni variable, which are named after Deneb. It is in the same direction and at the same distance as the faint open cluster An open cluster is a type of star cluster made of tens to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and ... NGC 6169, although it is brighter than the combined magnitude of all the other stars in the cluster. It was considered the prototype of the μ Normae class of open clusters by Collinder. References External links Jim Kaler's stars - Mu Normae {{DEFAULTSORT:Mu Normae O-type supergiants Norma (constellation) Alpha Cyg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Magnitude
Apparent magnitude () is a measure of the Irradiance, brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction (astronomy), extinction of the object's light caused by interstellar dust along the sightline, line of sight to the observer. Unless stated otherwise, the word ''magnitude'' in astronomy usually refers to a celestial object's apparent magnitude. The magnitude scale likely dates to before the ancient Ancient Greek astronomy#Astronomy in the Greco-Roman and Late Antique eras, Roman astronomer Ptolemy, Claudius Ptolemy, whose Star catalogue, star catalog popularized the system by listing stars from First-magnitude star, 1st magnitude (brightest) to 6th magnitude (dimmest). The modern scale was mathematically defined to closely match this historical system by Norman Robert Pogson, Norman Pogson in 1856. The scale is reverse logarithmic scale, logarithmic: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
88 Modern Constellations
In contemporary astronomy, 88 constellations are recognized by the International Astronomical Union (IAU). Each constellation is a region of the sky bordered by arcs of right ascension and declination, together covering the entire celestial sphere. Their boundaries were officially adopted by the International Astronomical Union in 1928 and published in 1930. The ancient Mesopotamians and later the Greek astronomy, Greeks established most of the northern constellations in international use today, listed by the Roman-Egyptian astronomer Ptolemy. The constellations along the ecliptic are called the zodiac. When explorers mapped the stars of the southern skies, European astronomers proposed new constellations for that region, as well as ones to fill gaps between the traditional constellations. Because of their Roman and European origins, every constellation has a Latin name. In 1922, the International Astronomical Union adopted three-letter abbreviations for 89 constellations, the m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spirit Level
A spirit level, bubble level, or simply a level, is an Measuring instrument, instrument designed to indicate whether a surface is Horizontal plane, horizontal (level) or vertical direction, vertical (plumb-bob, plumb). Two basic designs exist: ''tubular'' (or ''linear'') and ''Bull's eye level, bull's eye'' (or ''circular''). Different types of spirit levels may be used by carpenters, stonemasons, bricklayers, other building trades workers, Surveyor (surveying), surveyors, millwrights and other metalworkers, and in some Photography, photographic or Videography, videographic work. History The history of the spirit level was discussed in brief in an 1887 article appearing in ''Scientific American''. Melchisédech Thévenot, a French scientist, invented the instrument some time before February 2, 1661. This date can be established from Thevenot's correspondence with scientist Christiaan Huygens. Within a year of this date the inventor circulated details of his invention to othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
