আপাত মান

আপাত মান () গ্রহ, তারা বা অন্যান্য জ্যোতিষ্কের আপাত উজ্জ্বলতার একটি পরিমাপ। পৃথিবী থেকে একটি জ্যোতিষ্কের উজ্জ্বলতা যতটুকু দেখা যায় তার পরিমাপকে আপাত উজ্জ্বলতা বলে। এটি উজ্জ্বলতার একটি শ্রেণী বা প্রভা। একটি জ্যোতিষ্ক যত উজ্জ্বল হয় তার আপাত মান তত কম হয়।

 উল্লেখযোগ্য আকাশীয় বস্তুর টেবিল 
+ পরিচিত জ্যোতিষ্কসমূহের আপাত মান আপাত মান জ্যোতিষ্ক –38.00  Rigel as seen from 1 astronomical unit. It is seen as a large very bright bluish scorching ball of 35° apparent diameter. –30.30  Sirius as seen from 1 astronomical unit –29.30  Sun as seen from Mercury at perihelion –27.40  Sun as seen from Venus at perihelion –26.74  SunWilliams, Dr. David R. (2004-09-01). "Moon Fact Sheet" . NASA (National Space Science Data Center). Retrieved 2010-07-03. –25.60  Sun as seen from Mars at aphelion –23.00  Sun as seen from Jupiter at aphelion –21.70  Sun as seen from Saturn at aphelion –20.20  Sun as seen from Uranus at aphelion –19.30  Sun as seen from Neptune –18.20  Sun as seen from Pluto at aphelion –16.70  Sun as seen from Eris at aphelion –12.92  Maximum brightness of full Moon (mean is –12.74)Williams, Dr. David R. (2004-09-01). "Sun Fact Sheet" . NASA (National Space Science Data Center). Retrieved 2010-07-03. (398,359 times brighter than mean full moon) –11.20  Sun as seen from Sedna at aphelion –9.50  Maximum brightness of an Iridium (satellite) flare –7.50  The SN 1006 supernova of AD 1006, the brightest stellar event in recorded historyWinkler, P. Frank; Gupta, Gaurav; Long, Knox S. (2003). "The SN 1006 Remnant: Optical Proper Motions, Deep Imaging, Distance, and Brightness at Maximum". The Astrophysical Journal 585: 324–335. Bibcode 2003ApJ...585..324W. doi:10.1086/345985. –6.50  The total integrated magnitude of the night sky as seen from Earth –6.00  The Crab Supernova (SN 1054) of AD 1054 (6500 light years away) –5.9   International Space Station (when the ISS is at its perigee and fully lit by the sun) –4.89 Maximum brightness of Venus"HORIZONS Web-Interface for Venus (Major Body=299)". JPL Horizons On-Line Ephemeris System. 2006-Feb-27 (GEOPHYSICAL DATA). Retrieved 2010-11-28. (Using JPL Horizons you can see that on 2013-Dec-08 Venus will have an apmag of -4.89) when illuminated as a crescent –4.00 Faintest objects observable during the day with naked eye when Sun is high –3.99 Maximum brightness of Epsilon Canis Majoris, the brightest star of the last and next five million years –3.82 Minimum brightness of Venus when it is on the far side of the Sun –2.94 Maximum brightness of JupiterWilliams, David R. (2007-11-02). "Jupiter Fact Sheet" . National Space Science Data Center. NASA. Retrieved 2010-06-25. –2.91 Maximum brightness of MarsWilliams, David R. (2007-11-29). "Mars Fact Sheet" . National Space Science Data Center. NASA. Retrieved 2010-06-25. –2.50 Faintest objects visible during the day with naked eye when Sun is less than 10° above the horizon –2.50 Minimum brightness of new Moon –2.45 Maximum brightness of Mercury at superior conjunction (unlike Venus, Mercury is at its brightest when on the far side of the Sun) –1.61 Minimum brightness of Jupiter –1.47  Brightest star (except for the sun) at visible wavelengths: Sirius"Sirius". SIMBAD Astronomical Database. Retrieved 2010-06-26. –0.83  Eta Carinae apparent brightness as a supernova impostor in April 1843 –0.72  Second-brightest star: Canopus"Canopus". SIMBAD Astronomical Database. Retrieved 2010-06-26. –0.49 Maximum brightness of Saturn at opposition and when the rings are full open (2003, 2018) –0.27 The total magnitude for the Alpha Centauri AB star system. (Third-brightest star to the naked eye) –0.04  Fourth-brightest star to the naked eye Arcturus"Arcturus". SIMBAD Astronomical Database. Retrieved 2010-06-26. −0.01  Fourth-brightest individual star visible telescopically in the sky Alpha Centauri A +0.03 Vega, which was originally chosen as a definition of the zero point"Vega". SIMBAD Astronomical Database. Retrieved 2010-04-14. +0.50  Sun as seen from Alpha Centauri 1.47 Minimum brightness of Saturn 1.84 Minimum brightness of Mars 3.03 The SN 1987A supernova in the Large Magellanic Cloud 160,000 light-years away. 3 to 4 Faintest stars visible in an urban neighborhood with naked eye 3.44 The well known Andromeda Galaxy (M31)"SIMBAD-M31". SIMBAD Astronomical Database. Retrieved 2009-11-29. 4.38 Maximum brightness of GanymedeYeomans and Chamberlin. "Horizon Online Ephemeris System for Ganymede (Major Body 503)". California Institute of Technology, Jet Propulsion Laboratory. Retrieved 2010-04-14. (4.38 on 1951-Oct-03) (moon of Jupiter and the largest moon in the solar system) 4.50 M41, an open cluster that may have been seen by Aristotle 5.14 Maximum brightness of brightest asteroid Vesta 5.32 Maximum brightness of UranusWilliams, David R. (2005-01-31). "Uranus Fact Sheet". National Space Science Data Center. NASA. Retrieved 2010-06-25. 5.72 The spiral galaxy M33, which is used as a test for naked eye seeing under dark skies (shows b mag not v mag) 5.73 Minimum brightness of Mercury 5.8 Peak visual magnitude of gamma ray burst GRB 080319B (the "Clarke Event") seen on Earth on March 19, 2008 from a distance of 7.5 gigalight-years. 5.95 Minimum brightness of Uranus 6.40 Maximum brightness of asteroid Pallas 6.50 Approximate limit of stars observed by a mean naked eye observer under very good conditions. There are about 9,500 stars visible to mag 6.5."Vmag<6.5". SIMBAD Astronomical Database. Retrieved 2010-06-25. 6.73 Maximum brightness of dwarf planet Ceres in the asteroid belt 6.75 Maximum brightness of asteroid Iris 6.90 The spiral galaxy M81 is an extreme naked eye target that pushes human eyesight and the Bortle Dark-Sky Scale to the limit 7 to 8 Extreme naked eye limit with class 1 Bortle Dark-Sky Scale, the darkest skies available on Earth 7.72 The star HD 85828 is the faintest star known to be observed with the naked eye 7.78 Maximum brightness of NeptuneWilliams, David R. (2007-11-29). "Neptune Fact Sheet". National Space Science Data Center. NASA. Retrieved 2010-06-25. 8.02 Minimum brightness of Neptune 8.10 Maximum brightness of Titan (largest moon of Saturn),Yeomans and Chamberlin. "Horizon Online Ephemeris System for Titan (Major Body 606)". California Institute of Technology, Jet Propulsion Laboratory. Retrieved 2010-06-28. (8.10 on 2003-Dec-30)"Classic Satellites of the Solar System" . Observatorio ARVAL. Retrieved 2010-06-25. mean opposition magnitude 8.4"Planetary Satellite Physical Parameters". JPL (Solar System Dynamics). 2009-04-03. Retrieved 2009-07-25. 9.01 Maximum brightness of asteroid 10 Hygiea"AstDys (10) Hygiea Ephemerides". Department of Mathematics, University of Pisa, Italy. Retrieved 2010-06-26. 9.50 Faintest objects visible using common 7x50 binoculars under typical conditions 10.20 Maximum brightness of Iapetus (brightest when west of Saturn and takes 40 days to switch sides) 12.91  Brightest quasar 3C 273 (luminosity distance of 2.4 giga-light years) 13.42 Maximum brightness of Triton 13.65 Maximum brightness of PlutoWilliams, David R. (2006-09-07). "Pluto Fact Sheet" . National Space Science Data Center. NASA. Retrieved 2010-06-26. (725 times fainter than magnitude 6.5 naked eye skies) 15.40 Maximum brightness of centaur Chiron"AstDys (2060) Chiron Ephemerides". Department of Mathematics, University of Pisa, Italy. Retrieved 2010-06-26. 15.55 Maximum brightness of Charon (the large moon of Pluto) 16.80 Current opposition brightness of Makemake"AstDys (136472) Makemake Ephemerides". Department of Mathematics, University of Pisa, Italy. Retrieved 2010-06-26. 17.27 Current opposition brightness of Haumea"AstDys (136108) Haumea Ephemerides". Department of Mathematics, University of Pisa, Italy. Retrieved 2010-06-26. 18.70 Current opposition brightness of Eris 20.70 Callirrhoe (small ~8 km satellite of Jupiter) 22.00 Approximate limiting magnitude of a 24" Ritchey-Chrétien telescope with 30 minutes of stacked images (6 subframes at 300s each) using a ccd detector 22.91 Maximum brightness of Pluto's moon Hydra 23.38 Maximum brightness of Pluto's moon Nix 24.80 Amateur picture with greatest magnitude: quasar CFHQS J1641 +3755Cooperation with Ken Crawford 25.00 Fenrir (small ~4 km satellite of Saturn)Scott S. Sheppard. "Saturn's Known Satellites" . Carnegie Institution (Department of Terrestrial Magnetism). Retrieved 2010-06-28. 27.00 Faintest objects observable in visible light with 8m ground-based telescopes 28.00 Jupiter if it were located 5000AU from the SunMagnitude difference is 2.512*log10[(5000/5)^2 X (4999/4)^2] ≈ 30.6, so Jupiter is 30.6 mag fainter at 5000 AU 28.20 Halley's Comet in 2003 when it was 28AU from the Sun 31.50 Faintest objects observable in visible light with Hubble Space Telescope 35.00 Sedna at aphelion (900 AU) 35.00 LBV 1806-20 is a luminous blue variable star  at visible wavelengths 36.00 Faintest objects observable in visible light with E-ELT(see also List of brightest stars)
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 তথ্যসূত্র 

 বহিঃসংযোগ 
 The astronomical magnitude scale (International Comet Quarterly)

বিষয়শ্রেণী:পর্যবেক্ষণমূলক জ্যোতির্বিজ্ঞান
বিষয়শ্রেণী:পরিমাপের লগারিদমীয় মাপনী