| 1 | #include "erfa.h"
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| 2 |
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| 3 | void eraP06e(double date1, double date2,
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| 4 | double *eps0, double *psia, double *oma, double *bpa,
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| 5 | double *bqa, double *pia, double *bpia,
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| 6 | double *epsa, double *chia, double *za, double *zetaa,
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| 7 | double *thetaa, double *pa,
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| 8 | double *gam, double *phi, double *psi)
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| 9 | /*
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| 10 | ** - - - - - - - -
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| 11 | ** e r a P 0 6 e
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| 12 | ** - - - - - - - -
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| 13 | **
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| 14 | ** Precession angles, IAU 2006, equinox based.
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| 15 | **
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| 16 | ** Given:
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| 17 | ** date1,date2 double TT as a 2-part Julian Date (Note 1)
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| 18 | **
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| 19 | ** Returned (see Note 2):
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| 20 | ** eps0 double epsilon_0
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| 21 | ** psia double psi_A
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| 22 | ** oma double omega_A
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| 23 | ** bpa double P_A
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| 24 | ** bqa double Q_A
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| 25 | ** pia double pi_A
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| 26 | ** bpia double Pi_A
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| 27 | ** epsa double obliquity epsilon_A
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| 28 | ** chia double chi_A
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| 29 | ** za double z_A
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| 30 | ** zetaa double zeta_A
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| 31 | ** thetaa double theta_A
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| 32 | ** pa double p_A
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| 33 | ** gam double F-W angle gamma_J2000
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| 34 | ** phi double F-W angle phi_J2000
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| 35 | ** psi double F-W angle psi_J2000
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| 36 | **
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| 37 | ** Notes:
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| 38 | **
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| 39 | ** 1) The TT date date1+date2 is a Julian Date, apportioned in any
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| 40 | ** convenient way between the two arguments. For example,
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| 41 | ** JD(TT)=2450123.7 could be expressed in any of these ways,
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| 42 | ** among others:
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| 43 | **
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| 44 | ** date1 date2
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| 45 | **
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| 46 | ** 2450123.7 0.0 (JD method)
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| 47 | ** 2451545.0 -1421.3 (J2000 method)
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| 48 | ** 2400000.5 50123.2 (MJD method)
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| 49 | ** 2450123.5 0.2 (date & time method)
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| 50 | **
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| 51 | ** The JD method is the most natural and convenient to use in
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| 52 | ** cases where the loss of several decimal digits of resolution
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| 53 | ** is acceptable. The J2000 method is best matched to the way
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| 54 | ** the argument is handled internally and will deliver the
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| 55 | ** optimum resolution. The MJD method and the date & time methods
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| 56 | ** are both good compromises between resolution and convenience.
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| 57 | **
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| 58 | ** 2) This function returns the set of equinox based angles for the
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| 59 | ** Capitaine et al. "P03" precession theory, adopted by the IAU in
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| 60 | ** 2006. The angles are set out in Table 1 of Hilton et al. (2006):
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| 61 | **
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| 62 | ** eps0 epsilon_0 obliquity at J2000.0
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| 63 | ** psia psi_A luni-solar precession
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| 64 | ** oma omega_A inclination of equator wrt J2000.0 ecliptic
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| 65 | ** bpa P_A ecliptic pole x, J2000.0 ecliptic triad
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| 66 | ** bqa Q_A ecliptic pole -y, J2000.0 ecliptic triad
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| 67 | ** pia pi_A angle between moving and J2000.0 ecliptics
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| 68 | ** bpia Pi_A longitude of ascending node of the ecliptic
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| 69 | ** epsa epsilon_A obliquity of the ecliptic
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| 70 | ** chia chi_A planetary precession
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| 71 | ** za z_A equatorial precession: -3rd 323 Euler angle
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| 72 | ** zetaa zeta_A equatorial precession: -1st 323 Euler angle
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| 73 | ** thetaa theta_A equatorial precession: 2nd 323 Euler angle
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| 74 | ** pa p_A general precession
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| 75 | ** gam gamma_J2000 J2000.0 RA difference of ecliptic poles
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| 76 | ** phi phi_J2000 J2000.0 codeclination of ecliptic pole
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| 77 | ** psi psi_J2000 longitude difference of equator poles, J2000.0
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| 78 | **
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| 79 | ** The returned values are all radians.
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| 80 | **
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| 81 | ** 3) Hilton et al. (2006) Table 1 also contains angles that depend on
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| 82 | ** models distinct from the P03 precession theory itself, namely the
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| 83 | ** IAU 2000A frame bias and nutation. The quoted polynomials are
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| 84 | ** used in other ERFA functions:
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| 85 | **
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| 86 | ** . eraXy06 contains the polynomial parts of the X and Y series.
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| 87 | **
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| 88 | ** . eraS06 contains the polynomial part of the s+XY/2 series.
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| 89 | **
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| 90 | ** . eraPfw06 implements the series for the Fukushima-Williams
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| 91 | ** angles that are with respect to the GCRS pole (i.e. the variants
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| 92 | ** that include frame bias).
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| 93 | **
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| 94 | ** 4) The IAU resolution stipulated that the choice of parameterization
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| 95 | ** was left to the user, and so an IAU compliant precession
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| 96 | ** implementation can be constructed using various combinations of
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| 97 | ** the angles returned by the present function.
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| 98 | **
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| 99 | ** 5) The parameterization used by ERFA is the version of the Fukushima-
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| 100 | ** Williams angles that refers directly to the GCRS pole. These
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| 101 | ** angles may be calculated by calling the function eraPfw06. ERFA
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| 102 | ** also supports the direct computation of the CIP GCRS X,Y by
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| 103 | ** series, available by calling eraXy06.
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| 104 | **
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| 105 | ** 6) The agreement between the different parameterizations is at the
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| 106 | ** 1 microarcsecond level in the present era.
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| 107 | **
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| 108 | ** 7) When constructing a precession formulation that refers to the GCRS
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| 109 | ** pole rather than the dynamical pole, it may (depending on the
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| 110 | ** choice of angles) be necessary to introduce the frame bias
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| 111 | ** explicitly.
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| 112 | **
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| 113 | ** 8) It is permissible to re-use the same variable in the returned
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| 114 | ** arguments. The quantities are stored in the stated order.
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| 115 | **
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| 116 | ** Reference:
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| 117 | **
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| 118 | ** Hilton, J. et al., 2006, Celest.Mech.Dyn.Astron. 94, 351
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| 119 | **
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| 120 | ** Called:
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| 121 | ** eraObl06 mean obliquity, IAU 2006
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| 122 | **
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| 123 | ** Copyright (C) 2013-2016, NumFOCUS Foundation.
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| 124 | ** Derived, with permission, from the SOFA library. See notes at end of file.
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| 125 | */
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| 126 | {
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| 127 | double t;
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| 128 |
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| 129 |
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| 130 | /* Interval between fundamental date J2000.0 and given date (JC). */
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| 131 | t = ((date1 - ERFA_DJ00) + date2) / ERFA_DJC;
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| 132 |
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| 133 | /* Obliquity at J2000.0. */
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| 134 |
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| 135 | *eps0 = 84381.406 * ERFA_DAS2R;
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| 136 |
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| 137 | /* Luni-solar precession. */
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| 138 |
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| 139 | *psia = ( 5038.481507 +
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| 140 | ( -1.0790069 +
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| 141 | ( -0.00114045 +
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| 142 | ( 0.000132851 +
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| 143 | ( -0.0000000951 )
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| 144 | * t) * t) * t) * t) * t * ERFA_DAS2R;
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| 145 |
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| 146 | /* Inclination of mean equator with respect to the J2000.0 ecliptic. */
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| 147 |
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| 148 | *oma = *eps0 + ( -0.025754 +
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| 149 | ( 0.0512623 +
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| 150 | ( -0.00772503 +
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| 151 | ( -0.000000467 +
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| 152 | ( 0.0000003337 )
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| 153 | * t) * t) * t) * t) * t * ERFA_DAS2R;
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| 154 |
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| 155 | /* Ecliptic pole x, J2000.0 ecliptic triad. */
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| 156 |
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| 157 | *bpa = ( 4.199094 +
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| 158 | ( 0.1939873 +
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| 159 | ( -0.00022466 +
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| 160 | ( -0.000000912 +
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| 161 | ( 0.0000000120 )
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| 162 | * t) * t) * t) * t) * t * ERFA_DAS2R;
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| 163 |
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| 164 | /* Ecliptic pole -y, J2000.0 ecliptic triad. */
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| 165 |
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| 166 | *bqa = ( -46.811015 +
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| 167 | ( 0.0510283 +
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| 168 | ( 0.00052413 +
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| 169 | ( -0.000000646 +
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| 170 | ( -0.0000000172 )
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| 171 | * t) * t) * t) * t) * t * ERFA_DAS2R;
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| 172 |
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| 173 | /* Angle between moving and J2000.0 ecliptics. */
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| 174 |
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| 175 | *pia = ( 46.998973 +
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| 176 | ( -0.0334926 +
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| 177 | ( -0.00012559 +
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| 178 | ( 0.000000113 +
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| 179 | ( -0.0000000022 )
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| 180 | * t) * t) * t) * t) * t * ERFA_DAS2R;
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| 181 |
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| 182 | /* Longitude of ascending node of the moving ecliptic. */
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| 183 |
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| 184 | *bpia = ( 629546.7936 +
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| 185 | ( -867.95758 +
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| 186 | ( 0.157992 +
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| 187 | ( -0.0005371 +
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| 188 | ( -0.00004797 +
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| 189 | ( 0.000000072 )
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| 190 | * t) * t) * t) * t) * t) * ERFA_DAS2R;
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| 191 |
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| 192 | /* Mean obliquity of the ecliptic. */
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| 193 |
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| 194 | *epsa = eraObl06(date1, date2);
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| 195 |
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| 196 | /* Planetary precession. */
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| 197 |
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| 198 | *chia = ( 10.556403 +
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| 199 | ( -2.3814292 +
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| 200 | ( -0.00121197 +
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| 201 | ( 0.000170663 +
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| 202 | ( -0.0000000560 )
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| 203 | * t) * t) * t) * t) * t * ERFA_DAS2R;
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| 204 |
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| 205 | /* Equatorial precession: minus the third of the 323 Euler angles. */
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| 206 |
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| 207 | *za = ( -2.650545 +
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| 208 | ( 2306.077181 +
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| 209 | ( 1.0927348 +
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| 210 | ( 0.01826837 +
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| 211 | ( -0.000028596 +
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| 212 | ( -0.0000002904 )
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| 213 | * t) * t) * t) * t) * t) * ERFA_DAS2R;
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| 214 |
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| 215 | /* Equatorial precession: minus the first of the 323 Euler angles. */
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| 216 |
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| 217 | *zetaa = ( 2.650545 +
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| 218 | ( 2306.083227 +
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| 219 | ( 0.2988499 +
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| 220 | ( 0.01801828 +
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| 221 | ( -0.000005971 +
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| 222 | ( -0.0000003173 )
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| 223 | * t) * t) * t) * t) * t) * ERFA_DAS2R;
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| 224 |
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| 225 | /* Equatorial precession: second of the 323 Euler angles. */
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| 226 |
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| 227 | *thetaa = ( 2004.191903 +
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| 228 | ( -0.4294934 +
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| 229 | ( -0.04182264 +
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| 230 | ( -0.000007089 +
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| 231 | ( -0.0000001274 )
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| 232 | * t) * t) * t) * t) * t * ERFA_DAS2R;
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| 233 |
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| 234 | /* General precession. */
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| 235 |
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| 236 | *pa = ( 5028.796195 +
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| 237 | ( 1.1054348 +
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| 238 | ( 0.00007964 +
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| 239 | ( -0.000023857 +
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| 240 | ( 0.0000000383 )
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| 241 | * t) * t) * t) * t) * t * ERFA_DAS2R;
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| 242 |
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| 243 | /* Fukushima-Williams angles for precession. */
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| 244 |
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| 245 | *gam = ( 10.556403 +
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| 246 | ( 0.4932044 +
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| 247 | ( -0.00031238 +
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| 248 | ( -0.000002788 +
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| 249 | ( 0.0000000260 )
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| 250 | * t) * t) * t) * t) * t * ERFA_DAS2R;
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| 251 |
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| 252 | *phi = *eps0 + ( -46.811015 +
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| 253 | ( 0.0511269 +
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| 254 | ( 0.00053289 +
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| 255 | ( -0.000000440 +
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| 256 | ( -0.0000000176 )
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| 257 | * t) * t) * t) * t) * t * ERFA_DAS2R;
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| 258 |
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| 259 | *psi = ( 5038.481507 +
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| 260 | ( 1.5584176 +
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| 261 | ( -0.00018522 +
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| 262 | ( -0.000026452 +
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| 263 | ( -0.0000000148 )
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| 264 | * t) * t) * t) * t) * t * ERFA_DAS2R;
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| 265 |
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| 266 | return;
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| 267 |
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| 268 | }
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| 269 | /*----------------------------------------------------------------------
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| 270 | **
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| 271 | **
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| 272 | ** Copyright (C) 2013-2016, NumFOCUS Foundation.
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| 273 | ** All rights reserved.
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| 274 | **
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| 275 | ** This library is derived, with permission, from the International
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| 276 | ** Astronomical Union's "Standards of Fundamental Astronomy" library,
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| 277 | ** available from http://www.iausofa.org.
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| 278 | **
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| 279 | ** The ERFA version is intended to retain identical functionality to
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| 280 | ** the SOFA library, but made distinct through different function and
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| 281 | ** file names, as set out in the SOFA license conditions. The SOFA
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| 282 | ** original has a role as a reference standard for the IAU and IERS,
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| 283 | ** and consequently redistribution is permitted only in its unaltered
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| 284 | ** state. The ERFA version is not subject to this restriction and
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| 285 | ** therefore can be included in distributions which do not support the
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| 286 | ** concept of "read only" software.
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| 287 | **
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| 288 | ** Although the intent is to replicate the SOFA API (other than
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| 289 | ** replacement of prefix names) and results (with the exception of
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| 290 | ** bugs; any that are discovered will be fixed), SOFA is not
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| 291 | ** responsible for any errors found in this version of the library.
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| 292 | **
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| 293 | ** If you wish to acknowledge the SOFA heritage, please acknowledge
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| 294 | ** that you are using a library derived from SOFA, rather than SOFA
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| 295 | ** itself.
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| 296 | **
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| 297 | **
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| 298 | ** TERMS AND CONDITIONS
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| 299 | **
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| 300 | ** Redistribution and use in source and binary forms, with or without
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| 301 | ** modification, are permitted provided that the following conditions
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| 302 | ** are met:
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| 303 | **
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| 304 | ** 1 Redistributions of source code must retain the above copyright
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| 305 | ** notice, this list of conditions and the following disclaimer.
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| 306 | **
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| 307 | ** 2 Redistributions in binary form must reproduce the above copyright
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| 308 | ** notice, this list of conditions and the following disclaimer in
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| 309 | ** the documentation and/or other materials provided with the
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| 310 | ** distribution.
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| 311 | **
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| 312 | ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
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| 313 | ** the International Astronomical Union nor the names of its
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| 314 | ** contributors may be used to endorse or promote products derived
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| 315 | ** from this software without specific prior written permission.
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| 316 | **
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| 317 | ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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| 318 | ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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| 319 | ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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| 320 | ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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| 321 | ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 322 | ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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| 323 | ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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| 324 | ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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| 325 | ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 326 | ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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| 327 | ** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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| 328 | ** POSSIBILITY OF SUCH DAMAGE.
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| 329 | **
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| 330 | */
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