The bright star Vega has a parallax of 0.130 arcseconds,
  and an apparent magnitude m = 0.0.

         Q:  What is the distance to Vega, in parsecs?


                d  =  1.0 / 0.130  =  7.69 pc



         Q:  What is the absolute magnitude M of Vega?


                (m - M)  =  5 log(d)  -  5

                     M   =  m    -  [  5 log(d) - 5 ]

                         =  0.0  -  [  4.43  -  5  ]

                         =  0.57