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Diffstat (limited to 'ast/erfa/prec76.c')
| -rw-r--r-- | ast/erfa/prec76.c | 157 |
1 files changed, 0 insertions, 157 deletions
diff --git a/ast/erfa/prec76.c b/ast/erfa/prec76.c deleted file mode 100644 index 4c47985..0000000 --- a/ast/erfa/prec76.c +++ /dev/null @@ -1,157 +0,0 @@ -#include "erfa.h" - -void eraPrec76(double date01, double date02, double date11, double date12, - double *zeta, double *z, double *theta) -/* -** - - - - - - - - - - -** e r a P r e c 7 6 -** - - - - - - - - - - -** -** IAU 1976 precession model. -** -** This function forms the three Euler angles which implement general -** precession between two dates, using the IAU 1976 model (as for the -** FK5 catalog). -** -** Given: -** date01,date02 double TDB starting date (Note 1) -** date11,date12 double TDB ending date (Note 1) -** -** Returned: -** zeta double 1st rotation: radians cw around z -** z double 3rd rotation: radians cw around z -** theta double 2nd rotation: radians ccw around y -** -** Notes: -** -** 1) The dates date01+date02 and date11+date12 are Julian Dates, -** apportioned in any convenient way between the arguments daten1 -** and daten2. For example, JD(TDB)=2450123.7 could be expressed in -** any of these ways, among others: -** -** daten1 daten2 -** -** 2450123.7 0.0 (JD method) -** 2451545.0 -1421.3 (J2000 method) -** 2400000.5 50123.2 (MJD method) -** 2450123.5 0.2 (date & time method) -** -** The JD method is the most natural and convenient to use in cases -** where the loss of several decimal digits of resolution is -** acceptable. The J2000 method is best matched to the way the -** argument is handled internally and will deliver the optimum -** optimum resolution. The MJD method and the date & time methods -** are both good compromises between resolution and convenience. -** The two dates may be expressed using different methods, but at -** the risk of losing some resolution. -** -** 2) The accumulated precession angles zeta, z, theta are expressed -** through canonical polynomials which are valid only for a limited -** time span. In addition, the IAU 1976 precession rate is known to -** be imperfect. The absolute accuracy of the present formulation -** is better than 0.1 arcsec from 1960AD to 2040AD, better than -** 1 arcsec from 1640AD to 2360AD, and remains below 3 arcsec for -** the whole of the period 500BC to 3000AD. The errors exceed -** 10 arcsec outside the range 1200BC to 3900AD, exceed 100 arcsec -** outside 4200BC to 5600AD and exceed 1000 arcsec outside 6800BC to -** 8200AD. -** -** 3) The three angles are returned in the conventional order, which -** is not the same as the order of the corresponding Euler -** rotations. The precession matrix is -** R_3(-z) x R_2(+theta) x R_3(-zeta). -** -** Reference: -** -** Lieske, J.H., 1979, Astron.Astrophys. 73, 282, equations -** (6) & (7), p283. -** -** Copyright (C) 2013-2016, NumFOCUS Foundation. -** Derived, with permission, from the SOFA library. See notes at end of file. -*/ -{ - 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; - -} -/*---------------------------------------------------------------------- -** -** -** Copyright (C) 2013-2016, NumFOCUS Foundation. -** All rights reserved. -** -** This library is derived, with permission, from the International -** Astronomical Union's "Standards of Fundamental Astronomy" library, -** available from http://www.iausofa.org. -** -** The ERFA version is intended to retain identical functionality to -** the SOFA library, but made distinct through different function and -** file names, as set out in the SOFA license conditions. The SOFA -** original has a role as a reference standard for the IAU and IERS, -** and consequently redistribution is permitted only in its unaltered -** state. The ERFA version is not subject to this restriction and -** therefore can be included in distributions which do not support the -** concept of "read only" software. -** -** Although the intent is to replicate the SOFA API (other than -** replacement of prefix names) and results (with the exception of -** bugs; any that are discovered will be fixed), SOFA is not -** responsible for any errors found in this version of the library. -** -** If you wish to acknowledge the SOFA heritage, please acknowledge -** that you are using a library derived from SOFA, rather than SOFA -** itself. -** -** -** TERMS AND CONDITIONS -** -** Redistribution and use in source and binary forms, with or without -** modification, are permitted provided that the following conditions -** are met: -** -** 1 Redistributions of source code must retain the above copyright -** notice, this list of conditions and the following disclaimer. -** -** 2 Redistributions in binary form must reproduce the above copyright -** notice, this list of conditions and the following disclaimer in -** the documentation and/or other materials provided with the -** distribution. -** -** 3 Neither the name of the Standards Of Fundamental Astronomy Board, -** the International Astronomical Union nor the names of its -** contributors may be used to endorse or promote products derived -** from this software without specific prior written permission. -** -** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS -** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT -** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS -** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE -** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, -** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, -** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; -** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER -** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT -** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN -** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -** POSSIBILITY OF SUCH DAMAGE. -** -*/ |