Correcting Magnitudes for Distance
	• To correct intensity or flux for distance, use Inverse Square Law • Up to now we have used “apparent magnitudes”  mv • Define absolute magnitude Mv as magnitude star would have  if it were at a distance of 10 pc. • This gives us a way to correct Magnitude for distance, or find distance if we know absolute magnitude. Note:  the book writes mv and Mv:  The “V” stands for “Visual” -- Later we’ll consider magnitudes in other colors like “B=Blue” “U=Ultraviolet”