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Apparent Magnitude and Intensity Formula

  1. Mar 17, 2015 #1
    Hey,
    Could anyone explain why Ia/Ib=2.512^(Mb-Ma), Where "Ia" and "Ib" are intensities of star a and star b and "Mb" and "Ma" are the apparent magnitudes of star A and star B?

    I thought the formula would be Ia/Ib=(2.512)^(Ma-Mb) because Ia=2.512^Ma and Ib=2.512^Mb.

    Thank You
     
  2. jcsd
  3. Mar 17, 2015 #2

    wabbit

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    Gold Member

    Magnitude is an "inverse" scale in this sense : magnitude 0 is very bright (about the brightest visible stars), magnitude 10 is very faint (invisible naked eye). There's a minus sign missing in your formulas for la, lb.
     
    Last edited: Mar 17, 2015
  4. Mar 17, 2015 #3
    Thank you so much! So the actual relative intensity of magnitude 5 is 0.1 relative to the apparent magnitude 0?

    Thanks again!
     
  5. Mar 17, 2015 #4

    wabbit

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    Gold Member

  6. Mar 17, 2015 #5
    Thank You!!
     
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