jd2rotn

Source: utils/date_time/jd2rotn.pro

 jd2rotn
        Convert a julian day number to a rotation number

 Usage:
        rotn = jd2rotn(jd, system)

 Arguments:
        jd      double  input   The julian day to convert.
        system  int     input   0 for bartels, 1 for carrington

 Keyword:
        longitude       double  output  A variable to hold the
                                        longitude in degrees.

 History:
        Original: 23/8/00; SJT
        Fixed origin points: 6/6/01; SJT
        Added longitude keyword: 21/6/02; SJT