docs: def mjd2gmst(mjd):
      """Convert Modfied Juian Date (JD = 2400000.5) to GMST
      
      Taken from P.T. Walace routines.
  
      """
  
      tu = (mjd - MJD0) / (100*DPY)
  
      st = math.fmod(mjd, 1.0) * D2PI + (24110.54841 + (8640184.812866 + (0.093104 - 6.2e-6 * tu) * tu) * tu) * DS2R
  
      w = math.fmod(st, D2PI)
      if w >= 0.0:
          return w
      else:
          return w + D2PI