Unformatted text preview: Apparent Magnitude The apparent brightness of a star observed from the Earth is called the apparent magnitude . The apparent magnitude is a measure of the star's flux received by us. Here are some example apparent magnitudes: Sun = -26.7, Moon = -12.6, Venus = -4.4, Sirius = -1.4, Vega = 0.00, faintest naked eye star = +6.5, brightest quasar = +12.8, faintest object = +30 to +31. How do you do that? Star A has an apparent magnitude = 5.4 and star B has an apparent magnitude = 2.4. Which star is brighter and by how many times? Star B is brighter than star A because it has a lower apparent magnitude. Star B is brighter by 5.4 - 2.4 = 3 magnitudes. In terms of intensity star B is 2.512 (5.4- 2.4) = 2.512 3.0 = approximately 15.8 times brighter than star A. The amount of energy you receive from star B is almost 16 times greater than what you receive from star A. Absolute Magnitude and Luminosity If the star was at 10 parsecs distance from us, then its apparent magnitude would be equal to its...
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- Fall '10