আপাত মান

আপাত মান (ইংরেজি: Apparent magnitude; প্রতীক: m) 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।

গ্রহাণু ৬৫ সাইবেল এবং দু'টি তারাসহ তাদের বিশালত্ব

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	Sun^[১]
–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)^[২]
–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 history^[৩]
–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)^[৪]
–5.9	International Space Station (when the ISS is at its perigee and fully lit by the sun)^[৫]
–4.89	Maximum brightness of Venus^[৬] 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 Jupiter^[৭]
–2.91	Maximum brightness of Mars^[৮]
–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^[৯]
–0.83	Eta Carinae apparent brightness as a supernova impostor in April 1843
–0.72	Second-brightest star: Canopus^[১০]
–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^[১১]
−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^[১২]
+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)^[১৩]
4.38	Maximum brightness of Ganymede^[১৪] (moon of Jupiter and the largest moon in the solar system)
4.50	M41, an open cluster that may have been seen by Aristotle^[১৫]
5.14	Maximum brightness of brightest asteroid Vesta
5.32	Maximum brightness of Uranus^[১৬]
5.72	The spiral galaxy M33, which is used as a test for naked eye seeing under dark skies^[১৭]^[১৮]
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.^[১৯]
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^[২০]
7 to 8	Extreme naked eye limit with class 1 Bortle Dark-Sky Scale, the darkest skies available on Earth^[২১]
7.72	The star HD 85828^[২২] is the faintest star known to be observed with the naked eye^[২৩]
7.78	Maximum brightness of Neptune^[২৪]
8.02	Minimum brightness of Neptune
8.10	Maximum brightness of Titan (largest moon of Saturn),^[২৫]^[২৬] mean opposition magnitude 8.4^[২৭]
9.01	Maximum brightness of asteroid 10 Hygiea^[২৮]
9.50	Faintest objects visible using common 7x50 binoculars under typical conditions
10.20	Maximum brightness of Iapetus^[২৬] (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^[২৭]
13.65	Maximum brightness of Pluto^[২৯] (725 times fainter than magnitude 6.5 naked eye skies)
15.40	Maximum brightness of centaur Chiron^[৩০]
15.55	Maximum brightness of Charon (the large moon of Pluto)
16.80	Current opposition brightness of Makemake^[৩১]
17.27	Current opposition brightness of Haumea^[৩২]
18.70	Current opposition brightness of Eris
20.70	Callirrhoe (small ~8 km satellite of Jupiter)^[২৭]
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^[৩৩]
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 +3755^[৩৪]^[৩৫]
25.00	Fenrir (small ~4 km satellite of Saturn)^[৩৬]
27.00	Faintest objects observable in visible light with 8m ground-based telescopes
28.00	Jupiter if it were located 5000AU from the Sun^[৩৭]
28.20	Halley's Comet in 2003 when it was 28AU from the Sun^[৩৮]
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)

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