void eraPrec76	(	double	date01,
		double	date02,
		double	date11,
		double	date12,
		double *	zeta,
		double *	z,
		double *	theta
	)

Definition at line 3 of file prec76.c.

References ERFA_DAS2R, ERFA_DJ00, ERFA_DJC, and t.

Referenced by eraPmat76(), and t_prec76().

{
   double t0, t, tas2r, w;

/* Interval between fundamental epoch J2000.0 and start date (JC). */
   t0 = ((date01 - ERFA_DJ00) + date02) / ERFA_DJC;

/* Interval over which precession required (JC). */
   t = ((date11 - date01) + (date12 - date02)) / ERFA_DJC;

/* Euler angles. */
   tas2r = t * ERFA_DAS2R;
   w = 2306.2181 + (1.39656 - 0.000139 * t0) * t0;

   *zeta = (w + ((0.30188 - 0.000344 * t0) + 0.017998 * t) * t) * tas2r;

   *z = (w + ((1.09468 + 0.000066 * t0) + 0.018203 * t) * t) * tas2r;

   *theta = ((2004.3109 + (-0.85330 - 0.000217 * t0) * t0)
          + ((-0.42665 - 0.000217 * t0) - 0.041833 * t) * t) * tas2r;

   return;

}

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