Apparent and Absolute Magnitudes Apparent and Absolute Magnitudes Apparent Magnitude Apparent magnitude m of a star is a number that tells how bright that star appears at its great distance from Earth.
Larger magnitudes correspond to fainter stars.
Note that brightness is another way to say the flux of light , in Watts per square meter, coming towards us. On this magnitude scale, a brightness ratio of 100 is set to correspond exactly to a magnitude difference of 5. Absolute Magnitude Absolute magnitude M v is the apparent magnitude the star would have if it were placed at a distance of 10 parsecs from the Earth. Stars farther than 10 pc have M v more negative than m, that is why there is a minus sign in the formula. The above relation can also be used to determine the distance to a star if you know both its apparent magnitude and absolute magnitude.