code: def time_delay_from_location(self, other_location, right_ascension,
                                   declination, t_gps):
          
          ra_angle = self.gmst_estimate(t_gps) - right_ascension
          cosd = cos(declination)
  
          e0 = cosd * cos(ra_angle)
          e1 = cosd * -sin(ra_angle)
          e2 = sin(declination)
  
          ehat = np.array([e0, e1, e2])
          dx = other_location - self.location
          return dx.dot(ehat) / constants.c.value
docs: Return the time delay from the given location to detector for
          a signal with the given sky location
  
          In other words return `t1 - t2` where `t1` is the
          arrival time in this detector and `t2` is the arrival time in the
          other location.
  
          Parameters
          ----------
          other_location : numpy.ndarray of coordinates
              A detector instance.
          right_ascension : float
              The right ascension (in rad) of the signal.
          declination : float
              The declination (in rad) of the signal.
          t_gps : float
              The GPS time (in s) of the signal.
  
          Returns
          -------
          float
              The arrival time difference between the detectors.