[{"@context":"http:\/\/schema.org\/","@type":"BlogPosting","@id":"https:\/\/wiki.edu.vn\/all2en\/wiki32\/surface-shine-wikipedia\/#BlogPosting","mainEntityOfPage":"https:\/\/wiki.edu.vn\/all2en\/wiki32\/surface-shine-wikipedia\/","headline":"Surface shine – Wikipedia","name":"Surface shine – Wikipedia","description":"before-content-x4 A wikipedia article, free l’encyclop\u00e9i. after-content-x4 In astronomy, the surface shine of a celestial body extended as a galaxy","datePublished":"2019-05-27","dateModified":"2019-05-27","author":{"@type":"Person","@id":"https:\/\/wiki.edu.vn\/all2en\/wiki32\/author\/lordneo\/#Person","name":"lordneo","url":"https:\/\/wiki.edu.vn\/all2en\/wiki32\/author\/lordneo\/","image":{"@type":"ImageObject","@id":"https:\/\/secure.gravatar.com\/avatar\/44a4cee54c4c053e967fe3e7d054edd4?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/44a4cee54c4c053e967fe3e7d054edd4?s=96&d=mm&r=g","height":96,"width":96}},"publisher":{"@type":"Organization","name":"Enzyklop\u00e4die","logo":{"@type":"ImageObject","@id":"https:\/\/wiki.edu.vn\/wiki4\/wp-content\/uploads\/2023\/08\/download.jpg","url":"https:\/\/wiki.edu.vn\/wiki4\/wp-content\/uploads\/2023\/08\/download.jpg","width":600,"height":60}},"image":{"@type":"ImageObject","@id":"https:\/\/wikimedia.org\/api\/rest_v1\/media\/math\/render\/svg\/2a70107b7b6fc38d724b25cf309113285ea90fb9","url":"https:\/\/wikimedia.org\/api\/rest_v1\/media\/math\/render\/svg\/2a70107b7b6fc38d724b25cf309113285ea90fb9","height":"","width":""},"url":"https:\/\/wiki.edu.vn\/all2en\/wiki32\/surface-shine-wikipedia\/","wordCount":1651,"articleBody":"     (adsbygoogle = window.adsbygoogle || []).push({});before-content-x4A wikipedia article, free l’encyclop\u00e9i.        (adsbygoogle = window.adsbygoogle || []).push({});after-content-x4In astronomy, the surface shine of a celestial body extended as a galaxy designates the density of flow received per unit of solid angle. It is often measured in magnitude per second from Arc au Carr\u00e9 ( mag\/as 2 ). Some authors also give this measure by using the arc minute. The units of surface shine are then ( Mag\/Am 2 ) The measurement of surface shine in visible wavelengths, or in infrared, is photometry.        (adsbygoogle = window.adsbygoogle || []).push({});after-content-x4The bottom of the sky designates the surface shine of the sky.   The apparent magnitude of an astronomical object is generally given as an integral measure: if it is said that a galaxy has a magnitude of 12.5, this means that we receive the same amount of light from this galaxy as that that would make a star of magnitude 12.5. However, a star is generally so small that it appears as a punctual source to most observations (the largest angular diameter of a star is that of R Doradus, which is 0.057 \u00b1 0.005 arcsec ), while a galaxy can extend over many seconds of arc, even minutes of arc. Therefore, a galaxy can be more difficult to perceive on the bottom of the night sky than an isolated star. Global magnitude is a measure of the shine of an extensive object, for example a nebula, a stellar cluster, or a galaxy. It can be determined by integrating the brightness on the entire surface of this object. Alternatively, it is possible to use a photometer by adjusting the field covered by diaphragms of various sizes [ first ] . The background light is then subtracted from the measurements to obtain the total shine [ 2 ] .        (adsbygoogle = window.adsbygoogle || []).push({});after-content-x4The resulting magnitude value is that of a punctual source that would emout the same amount of energy [ 3 ] Apparent magnitude is a good indicator of the visibility of an object when it is almost punctual; On the contrary, the surface shine is a better indicator when this object has a visible angular surface. The surface shines are generally expressed in magnitude by second square arc or magnitude by minute of square arc. Since magnitude is logarithmic, the calculation of the shine of the surface cannot be carried out by a simple division of magnitude by the surface of the object considered. The equation used calls on the base 10: S = m + 2 , 5 \u00d7 log 10\u2061 A {displaystyle S=m+2,5times log _{10}A}  Or S is the surface shine, m magnitude and A the surface in seconds of arc or in minutes of arc. Since the equation contains two variables, M and A, there is no way to directly convert the MAG\/AS value 2 and MAG\/AM 2 . You have to know the two variables to make this conversion. A truly dark sky has a surface light of 2 \u00d7 10 \u22124 CD M \u22122 or 21.8 MAG Arcsec \u22122 [ 4 ] . The maximum surface light of the central region of the Orion nebula is around 17 Mag\/Arcsec 2 (Environment 14 Milli CD\/M 2 (formerly nits)) and external bluish glow has a maximum surface light of 21.3 Mag\/Arcsec 2 (environ 0.27 millinits) [ 5 ] . \u2191 (in) Daintith, John et Gould, William, The Facts on File dictionary of astronomy , Infobase Publishing, coll. \u00a0\u00ab\u00a0Facts on File science library\u00a0\u00bb, 2006 , 5 It is  ed.  (ISBN\u00a0 0-8160-5998-5 ) , p. 489  \u2191 (in) A. B. Along , ‘ Integrating Photometers \u00bb , Soviet Astronomy , vol. 12, August 1968 , p. 164 (Bibcode\u00a0 1968SvA….12..164P)  \u2191 (in) Sherrod, P. Clay et Koed, Thomas L., A Complete Manual of Amateur Astronomy\u00a0: Tools and Techniques for Astronomical Observations , Courier Dover Publications, coll. \u00a0\u00ab\u00a0Astronomy Series\u00a0\u00bb, 2003 (ISBN\u00a0 0-486-42820-6 ) , p. 266  \u2191 Based on the equivalence 21.83\u00a0mag\u00a0arcsec \u22122 = 2 \u00d7 10 \u22124 CD M \u22122 , from description of a “truly dark sky”, Section 1.3 of Crumey, A. (2014). Human contrast threshold and astronomical visibility. MNRAS 442, 2600\u20132619.  \u2191 Roger Clark , ‘ Surface Brightness of Deep Sky Objects \u00bb , 28 mars 2004 (consulted the June 29, 2013 ) . The conversion to nits is based on 0 magnitude being 2.08 microlux.         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