What is the difference between absolute magnitude and apparent magnitude?
The absolute magnitude is the brightness a star would have if it was a standard distance of 10 parsec (32.6 light years or so) from us. Apparent magnitude is how bright the object appears now, given that very brigh objects located far may appear less bright than less luminous ones that are closer. Thus, our sun has a very important apparent magnitude, but given that it is a small star, has a very puny absolute magnitude. For the record, magnitude of brighter object is a smaller numerical value than fainter ones. The sun has a -26.7 (that is minus 26) apparent magnitude (and 4.83 absolute magnitude) , and the naked eye can see, under ideal conditions, objects of magnitude +6 (Hubble telescope can go to +30). In a urban area, because of light pollution, the maximum you can achieve with the naked eye is about +3; which means the sun would not even be visible for the average person living in a city if it was only 32 light years away.
