code: def ut1_jd(self, jd):
          
          ut1 = _to_array(jd)
  
          # Estimate TT = UT1, to get a rough Delta T estimate.
          tt_approx = ut1
          delta_t_approx = interpolate_delta_t(self.delta_t_table, tt_approx)
  
          # Use the rough Delta T to make a much better estimate of TT,
          # then generate an even better Delta T.
          tt_approx = ut1 + delta_t_approx / DAY_S
          delta_t_approx = interpolate_delta_t(self.delta_t_table, tt_approx)
  
          # We can now estimate TT with an error of < 1e-9 seconds within
          # 10 centuries of either side of the present; for details, see:
          # https://github.com/skyfielders/astronomy-notebooks
          # and look for the notebook "error-in-timescale-ut1.ipynb".
          tt = ut1 + delta_t_approx / DAY_S
          t = Time(self, tt)
          t.ut1 = ut1
          return t
docs: Build a `Time` from UT1 a Julian date.
  
          Supply the Universal Time (UT1) as a Julian date:
  
          >>> t = ts.ut1_jd(2456675.56640625)
          >>> t.ut1
          2456675.56640625