
#1
Dec612, 09:42 PM

P: 31

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: m_{a}m_{b}= 2.5log_{10}[itex]\left( \frac{F_a}{F_b}\right)[/itex] but I just have F_{a} and I have to obtain m_{a}. Is it valid to take m_{a}=2.5log_{10} F_{a}? 



#2
Dec712, 05:22 AM

Homework
Sci Advisor
HW Helper
Thanks ∞
PF Gold
P: 10,916

the "b" indexed values would have to be some reference value that depends on the scale you are using.
http://en.wikipedia.org/wiki/Apparen...ference_Values 



#3
Dec712, 07:53 AM

P: 31

Ok, but in that table the values for "m" don't appear, only the fluxes :s




#4
Dec712, 08:37 AM

Homework
Sci Advisor
HW Helper
Thanks ∞
PF Gold
P: 10,916

Flux & apparent magnitudeSpecifically: you should not get your referencevalues 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. 


Register to reply 
Related Discussions  
absolute and apparent magnitude  General Physics  1  
Calculating absolute magnitude and apparent magnitude  Advanced Physics Homework  1  
Apparent Magnitude Problem  General Astronomy  1  
Apparent Magnitude  General Astronomy  3  
Apparent magnitude  Introductory Physics Homework  1 