L(HV)   =   2.03  x  10^(31)    W

     L(Sun)  =   3.83  x  10^(26)    W


So the absolute magnitude of the HV system can be calculated as


                                                          2.03 x 10^(31)
       (abs mag HV)   =   (abs mag Sun)  -  2.5 * log10 ( -------------- )
                                                          3.83 x 10^(26)


                      =    4.83    -   11.81


                      =    -6.98