void eraBp00	(	double	date1,
		double	date2,
		double	rb[3][3],
		double	rp[3][3],
		double	rbp[3][3]
	)

Definition at line 3 of file bp00.c.

References eraBi00(), eraCr(), eraIr(), eraPr00(), eraRx(), eraRxr(), eraRy(), eraRz(), ERFA_DAS2R, ERFA_DJ00, ERFA_DJC, and t.

Referenced by eraPmat00(), eraPn00(), and t_bp00().

{
/* J2000.0 obliquity (Lieske et al. 1977) */
   const double EPS0 = 84381.448 * ERFA_DAS2R;

   double t, dpsibi, depsbi, dra0, psia77, oma77, chia,
          dpsipr, depspr, psia, oma, rbw[3][3];

/* Interval between fundamental epoch J2000.0 and current date (JC). */
   t = ((date1 - ERFA_DJ00) + date2) / ERFA_DJC;

/* Frame bias. */
   eraBi00(&dpsibi, &depsbi, &dra0);

/* Precession angles (Lieske et al. 1977) */
   psia77 = (5038.7784 + (-1.07259 + (-0.001147) * t) * t) * t * ERFA_DAS2R;
   oma77  =       EPS0 + ((0.05127 + (-0.007726) * t) * t) * t * ERFA_DAS2R;
   chia   = (  10.5526 + (-2.38064 + (-0.001125) * t) * t) * t * ERFA_DAS2R;

/* Apply IAU 2000 precession corrections. */
   eraPr00(date1, date2, &dpsipr, &depspr);
   psia = psia77 + dpsipr;
   oma  = oma77  + depspr;

/* Frame bias matrix: GCRS to J2000.0. */
   eraIr(rbw);
   eraRz(dra0, rbw);
   eraRy(dpsibi*sin(EPS0), rbw);
   eraRx(-depsbi, rbw);
   eraCr(rbw, rb);

/* Precession matrix: J2000.0 to mean of date. */
   eraIr(rp);
   eraRx(EPS0, rp);
   eraRz(-psia, rp);
   eraRx(-oma, rp);
   eraRz(chia, rp);

/* Bias-precession matrix: GCRS to mean of date. */
   eraRxr(rp, rbw, rbp);

   return;

}

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