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Flux & apparent magnitude

  1. Dec 6, 2012 #1
    How to calculate the visual magnitude of a star having only the flux of such star?
    The equation involves 2 magnitudes and 2 fluxes, corresponding to 2 objects a and b:

    ma-mb= -2.5log10[itex]\left( \frac{F_a}{F_b}\right)[/itex]

    but I just have Fa and I have to obtain ma.

    Is it valid to take ma=-2.5log10 Fa?
     
  2. jcsd
  3. Dec 7, 2012 #2

    Simon Bridge

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  4. Dec 7, 2012 #3
    Ok, but in that table the values for "m" don't appear, only the fluxes :-s
     
  5. Dec 7, 2012 #4

    Simon Bridge

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    ... yes they do: right at the top of the 4th and 5th columns where it says "m=0". But you can use any reference values that make sense in terms of your coursework.
    Specifically: you should not get your reference-values off wikipedia. You must have access to a library or a text book or something like that?
    In a pinch - go to wikipedias primary source.
     
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