Tuesday, March 19, 2013

Answer To Question 217

A 217: The brightness ratio is a comparison of the brightness of two celestial objects (like stars or planets). The brightness ratio is defined as 2.512 raised to the difference of the magnitudes of the objects (since the magnitude scale is logarithmic and the difference in each successive magnitude is a factor of about 2.512 times). For example, a 1st magnitude star is 2.512 times brighter than a 2nd magnitude star (their brightness ration is 2.512). For another example, if two objects have magnitudes of 2 and 7 (a difference of 5), their brightness ratio is 2.512 raised to the 5th power, which is about 100.

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