reply to post by wildespace
Apparent
magnitude Brightness
relative to
magnitude 0 Example Apparent
magnitude Brightness
relative to
magnitude 0 Example Apparent
magnitude Brightness
relative to
magnitude 0 Example
−27 6.3×1010 Sun −7 630 SN 1006 supernova 13 6.3×10−6 3C 273 quasar
−26 2.5×1010 −6 250 ISS (max) 14 2.5×10−6 Pluto (max)
−25 1.0×1010 −5 100 Venus (max) 15 1.0×10−6
−24 4.0×109 −4 40 16 4.0×10−7 Charon (max)
−23 1.6×109 −3 16 Jupiter (max), Mars (max) 17 1.6×10−7
−22 6.3×108 −2 6.3 Mercury (max) 18 6.3×10−8
−21 2.5×108 −1 2.5 Sirius 19 2.5×10−8
−20 1.0×108 0 1.0 Vega, Saturn (max) 20 1.0×10−8
−19 4.0×107 1 0.40 Antares 21 4.0×10−9 Callirrhoe (satellite of Jupiter)
−18 1.6×107 2 0.16 Polaris 22 1.6×10−9
−17 6.3×106 3 0.063 Cor Caroli 23 6.3×10−10
−16 2.5×106 4 0.025 Acubens 24 2.5×10−10
−15 1.0×106 5 0.010 Vesta (max), Uranus (max) 25 1.0×10−10 Fenrir (satellite of Saturn)
−14 4.0×105 6 4.0×10−3 typical limit of naked eye[note 1] 26 4.0×10−11
−13 1.6×105 Full Moon 7 1.6×10−3 Ceres (max) 27 1.6×10−11 visible light limit of 8m telescopes
−12 6.3×104 8 6.3×10−4 Neptune (max) 28 6.3×10−12
−11 2.5×104 9 2.5×10−4 29 2.5×10−12
−10 1.0×104 10 1.0×10−4 typical limit of 7x50 binoculars 30 1.0×10−12
−9 4.0×103 Iridium flare 11 4.0×10−5 31 4.0×10−13
−8 1.6×103 12 1.6×10−5 32 1.6×10−13 visible light limit of HST
en.wikipedia.org...(astronomy)
edit on 30-9-2012 by ResearchEverything777 because: add link
Yes! Variations of Visible Light...
Absolute scale based on Vega
"Main article: Absolute magnitude
The star Vega has been defined as having a magnitude of zero, or at least near. Modern instruments such as bolometers and radiometers give Vega a
brightness of about 0.03. The brightest star, Sirius, has a magnitude of −1.46. or −1.5. However, Vega has been found to vary in brightness, and
other standards have been proposed.
Problems
The human eye is easily fooled, and Hipparchus's scale has had problems. For example, the human eye is more sensitive to yellow/red light than to
blue, and photographic film more to blue than to yellow/red, giving different values of visual magnitude and photographic magnitude. Furthermore, many
people find it counter-intuitive that a high magnitude star is dimmer than a low magnitude star.
Apparent and absolute magnitude
Two specific types of magnitudes distinguished by astronomers are:
Apparent magnitude, the apparent brightness of an object. For example, Alpha Centauri has higher apparent magnitude (i.e. lower value) than
Betelgeuse, because it is much closer to the Earth.
Absolute magnitude, which measures the luminosity of an object (or reflected light for non-luminous objects like asteroids); it is the object's
apparent magnitude as seen from a certain distance. For stars it is 10 parsecs (32.6 light years). Betelgeuse has much higher absolute magnitude than
Alpha Centauri, because it is much more luminous.
Usually only apparent magnitude is mentioned, because it can be measured directly; absolute magnitude can be calculated from apparent magnitude and
distance using;
This is known as the distance modulus, where d is the distance to the star measured in parsecs."
en.wikipedia.org...(astronomy)
edit on 30-9-2012 by ResearchEverything777 because: add
text
edit on 30-9-2012 by ResearchEverything777 because: remove text