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erfasrc/src/eect00.c  view on Meta::CPAN

**
**     Capitaine, N. & Gontier, A.-M., Astron.Astrophys., 275,
**     645-650 (1993)
**
**     Capitaine, N., Wallace, P.T. and McCarthy, D.D., "Expressions to
**     implement the IAU 2000 definition of UT1", Astron.Astrophys., 406,
**     1135-1149 (2003)
**
**     IAU Resolution C7, Recommendation 3 (1994)
**
**     McCarthy, D. D., Petit, G. (eds.), IERS Conventions (2003),
**     IERS Technical Note No. 32, BKG (2004)
**
**  Copyright (C) 2013-2020, NumFOCUS Foundation.
**  Derived, with permission, from the SOFA library.  See notes at end of file.
*/
{
/* Time since J2000.0, in Julian centuries */
   double t;

/* Miscellaneous */
   int i, j;
   double a, s0, s1;

/* Fundamental arguments */
   double fa[14];

/* Returned value. */
   double eect;

/* ----------------------------------------- */
/* The series for the EE complementary terms */
/* ----------------------------------------- */

   typedef struct {
      int nfa[8];      /* coefficients of l,l',F,D,Om,LVe,LE,pA */
      double s, c;     /* sine and cosine coefficients */
   } TERM;

/* Terms of order t^0 */
   static const TERM e0[] = {

   /* 1-10 */
      {{ 0,  0,  0,  0,  1,  0,  0,  0}, 2640.96e-6, -0.39e-6 },
      {{ 0,  0,  0,  0,  2,  0,  0,  0},   63.52e-6, -0.02e-6 },
      {{ 0,  0,  2, -2,  3,  0,  0,  0},   11.75e-6,  0.01e-6 },
      {{ 0,  0,  2, -2,  1,  0,  0,  0},   11.21e-6,  0.01e-6 },
      {{ 0,  0,  2, -2,  2,  0,  0,  0},   -4.55e-6,  0.00e-6 },
      {{ 0,  0,  2,  0,  3,  0,  0,  0},    2.02e-6,  0.00e-6 },
      {{ 0,  0,  2,  0,  1,  0,  0,  0},    1.98e-6,  0.00e-6 },
      {{ 0,  0,  0,  0,  3,  0,  0,  0},   -1.72e-6,  0.00e-6 },
      {{ 0,  1,  0,  0,  1,  0,  0,  0},   -1.41e-6, -0.01e-6 },
      {{ 0,  1,  0,  0, -1,  0,  0,  0},   -1.26e-6, -0.01e-6 },

   /* 11-20 */
      {{ 1,  0,  0,  0, -1,  0,  0,  0},   -0.63e-6,  0.00e-6 },
      {{ 1,  0,  0,  0,  1,  0,  0,  0},   -0.63e-6,  0.00e-6 },
      {{ 0,  1,  2, -2,  3,  0,  0,  0},    0.46e-6,  0.00e-6 },
      {{ 0,  1,  2, -2,  1,  0,  0,  0},    0.45e-6,  0.00e-6 },
      {{ 0,  0,  4, -4,  4,  0,  0,  0},    0.36e-6,  0.00e-6 },
      {{ 0,  0,  1, -1,  1, -8, 12,  0},   -0.24e-6, -0.12e-6 },
      {{ 0,  0,  2,  0,  0,  0,  0,  0},    0.32e-6,  0.00e-6 },
      {{ 0,  0,  2,  0,  2,  0,  0,  0},    0.28e-6,  0.00e-6 },
      {{ 1,  0,  2,  0,  3,  0,  0,  0},    0.27e-6,  0.00e-6 },
      {{ 1,  0,  2,  0,  1,  0,  0,  0},    0.26e-6,  0.00e-6 },

   /* 21-30 */
      {{ 0,  0,  2, -2,  0,  0,  0,  0},   -0.21e-6,  0.00e-6 },
      {{ 0,  1, -2,  2, -3,  0,  0,  0},    0.19e-6,  0.00e-6 },
      {{ 0,  1, -2,  2, -1,  0,  0,  0},    0.18e-6,  0.00e-6 },
      {{ 0,  0,  0,  0,  0,  8,-13, -1},   -0.10e-6,  0.05e-6 },
      {{ 0,  0,  0,  2,  0,  0,  0,  0},    0.15e-6,  0.00e-6 },
      {{ 2,  0, -2,  0, -1,  0,  0,  0},   -0.14e-6,  0.00e-6 },
      {{ 1,  0,  0, -2,  1,  0,  0,  0},    0.14e-6,  0.00e-6 },
      {{ 0,  1,  2, -2,  2,  0,  0,  0},   -0.14e-6,  0.00e-6 },
      {{ 1,  0,  0, -2, -1,  0,  0,  0},    0.14e-6,  0.00e-6 },
      {{ 0,  0,  4, -2,  4,  0,  0,  0},    0.13e-6,  0.00e-6 },

   /* 31-33 */
      {{ 0,  0,  2, -2,  4,  0,  0,  0},   -0.11e-6,  0.00e-6 },
      {{ 1,  0, -2,  0, -3,  0,  0,  0},    0.11e-6,  0.00e-6 },
      {{ 1,  0, -2,  0, -1,  0,  0,  0},    0.11e-6,  0.00e-6 }
   };

/* Terms of order t^1 */
   static const TERM e1[] = {
      {{ 0,  0,  0,  0,  1,  0,  0,  0},    -0.87e-6,  0.00e-6 }
   };

/* Number of terms in the series */
   const int NE0 = (int) (sizeof e0 / sizeof (TERM));
   const int NE1 = (int) (sizeof e1 / sizeof (TERM));

/* ------------------------------------------------------------------ */

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

/* Fundamental Arguments (from IERS Conventions 2003) */

/* Mean anomaly of the Moon. */
   fa[0] = eraFal03(t);

/* Mean anomaly of the Sun. */
   fa[1] = eraFalp03(t);

/* Mean longitude of the Moon minus that of the ascending node. */
   fa[2] = eraFaf03(t);

/* Mean elongation of the Moon from the Sun. */
   fa[3] = eraFad03(t);

/* Mean longitude of the ascending node of the Moon. */
   fa[4] = eraFaom03(t);

/* Mean longitude of Venus. */
   fa[5] = eraFave03(t);

/* Mean longitude of Earth. */
   fa[6] = eraFae03(t);