#include "erfa.h"
int eraApco13(double utc1, double utc2, double dut1,
double elong, double phi, double hm, double xp, double yp,
double phpa, double tc, double rh, double wl,
eraASTROM *astrom, double *eo)
/*
** - - - - - - - - - -
** e r a A p c o 1 3
** - - - - - - - - - -
**
** For a terrestrial observer, prepare star-independent astrometry
** parameters for transformations between ICRS and observed
** coordinates. The caller supplies UTC, site coordinates, ambient air
** conditions and observing wavelength, and ERFA models are used to
** obtain the Earth ephemeris, CIP/CIO and refraction constants.
**
** The parameters produced by this function are required in the
** parallax, light deflection, aberration, and bias-precession-nutation
** parts of the ICRS/CIRS transformations.
**
** Given:
** utc1 double UTC as a 2-part...
** utc2 double ...quasi Julian Date (Notes 1,2)
** dut1 double UT1-UTC (seconds, Note 3)
** elong double longitude (radians, east +ve, Note 4)
** phi double latitude (geodetic, radians, Note 4)
** hm double height above ellipsoid (m, geodetic, Notes 4,6)
** xp,yp double polar motion coordinates (radians, Note 5)
** phpa double pressure at the observer (hPa = mB, Note 6)
** tc double ambient temperature at the observer (deg C)
** rh double relative humidity at the observer (range 0-1)
** wl double wavelength (micrometers, Note 7)
**
** Returned:
** astrom eraASTROM* star-independent astrometry parameters:
** pmt double PM time interval (SSB, Julian years)
** eb double[3] SSB to observer (vector, au)
** eh double[3] Sun to observer (unit vector)
** em double distance from Sun to observer (au)
** v double[3] barycentric observer velocity (vector, c)
** bm1 double sqrt(1-|v|^2): reciprocal of Lorenz factor
** bpn double[3][3] bias-precession-nutation matrix
** along double longitude + s' (radians)
** xpl double polar motion xp wrt local meridian (radians)
** ypl double polar motion yp wrt local meridian (radians)
** sphi double sine of geodetic latitude
** cphi double cosine of geodetic latitude
** diurab double magnitude of diurnal aberration vector
** eral double "local" Earth rotation angle (radians)
** refa double refraction constant A (radians)
** refb double refraction constant B (radians)
** eo double* equation of the origins (ERA-GST)
**
** Returned (function value):
** int status: +1 = dubious year (Note 2)
** 0 = OK
** -1 = unacceptable date
**
** Notes:
**
** 1) utc1+utc2 is quasi Julian Date (see Note 2), apportioned in any
** convenient way between the two arguments, for example where utc1
** is the Julian Day Number and utc2 is the fraction of a day.
**
** However, JD cannot unambiguously represent UTC during a leap
** second unless special measures are taken. The convention in the
** present function is that the JD day represents UTC days whether
** the length is 86399, 86400 or 86401 SI seconds.
**
** Applications should use the function eraDtf2d to convert from
** calendar date and time of day into 2-part quasi Julian Date, as
** it implements the leap-second-ambiguity convention just
** described.
**
** 2) The warning status "dubious year" flags UTCs that predate the
** introduction of the time scale or that are too far in the
** future to be trusted. See eraDat for further details.
**
** 3) UT1-UTC is tabulated in IERS bulletins. It increases by exactly
** one second at the end of each positive UTC leap second,
** introduced in order to keep UT1-UTC within +/- 0.9s. n.b. This
** practice is under review, and in the future UT1-UTC may grow
** essentially without limit.
**
** 4) The geographical coordinates are with respect to the ERFA_WGS84
** reference ellipsoid. TAKE CARE WITH THE LONGITUDE SIGN: the
** longitude required by the present function is east-positive
** (i.e. right-handed), in accordance with geographical convention.
**
** 5) The polar motion xp,yp can be obtained from IERS bulletins. The
** values are the coordinates (in radians) of the Celestial
** Intermediate Pole with respect to the International Terrestrial
** Reference System (see IERS Conventions 2003), measured along the
** meridians 0 and 90 deg west respectively. For many
** applications, xp and yp can be set to zero.
**
** Internally, the polar motion is stored in a form rotated onto
** the local meridian.
**
** 6) If hm, the height above the ellipsoid of the observing station
** in meters, is not known but phpa, the pressure in hPa (=mB), is
** available, an adequate estimate of hm can be obtained from the
** expression
**
** hm = -29.3 * tsl * log ( phpa / 1013.25 );
**
** where tsl is the approximate sea-level air temperature in K
** (See Astrophysical Quantities, C.W.Allen, 3rd edition, section
** 52). Similarly, if the pressure phpa is not known, it can be
** estimated from the height of the observing station, hm, as
** follows:
**
** phpa = 1013.25 * exp ( -hm / ( 29.3 * tsl ) );
**
** Note, however, that the refraction is nearly proportional to
** the pressure and that an accurate phpa value is important for
** precise work.
**
** 7) The argument wl specifies the observing wavelength in
** micrometers. The transition from optical to radio is assumed to
** occur at 100 micrometers (about 3000 GHz).
**
** 8) It is advisable to take great care with units, as even unlikely
** values of the input parameters are accepted and processed in
** accordance with the models used.
**
** 9) In cases where the caller wishes to supply his own Earth
** ephemeris, Earth rotation information and refraction constants,
** the function eraApco can be used instead of the present function.
**
** 10) This is one of several functions that inserts into the astrom
** structure star-independent parameters needed for the chain of
** astrometric transformations ICRS <-> GCRS <-> CIRS <-> observed.
**
** The various functions support different classes of observer and
** portions of the transformation chain:
**
** functions observer transformation
**
** eraApcg eraApcg13 geocentric ICRS <-> GCRS
** eraApci eraApci13 terrestrial ICRS <-> CIRS
** eraApco eraApco13 terrestrial ICRS <-> observed
** eraApcs eraApcs13 space ICRS <-> GCRS
** eraAper eraAper13 terrestrial update Earth rotation
** eraApio eraApio13 terrestrial CIRS <-> observed
**
** Those with names ending in "13" use contemporary ERFA models to
** compute the various ephemerides. The others accept ephemerides
** supplied by the caller.
**
** The transformation from ICRS to GCRS covers space motion,
** parallax, light deflection, and aberration. From GCRS to CIRS
** comprises frame bias and precession-nutation. From CIRS to
** observed takes account of Earth rotation, polar motion, diurnal
** aberration and parallax (unless subsumed into the ICRS <-> GCRS
** transformation), and atmospheric refraction.
**
** 11) The context structure astrom produced by this function is used
** by eraAtioq, eraAtoiq, eraAtciq* and eraAticq*.
**
** Called:
** eraUtctai UTC to TAI
** eraTaitt TAI to TT
** eraUtcut1 UTC to UT1
** eraEpv00 Earth position and velocity
** eraPnm06a classical NPB matrix, IAU 2006/2000A
** eraBpn2xy extract CIP X,Y coordinates from NPB matrix
** eraS06 the CIO locator s, given X,Y, IAU 2006
** eraEra00 Earth rotation angle, IAU 2000
** eraSp00 the TIO locator s', IERS 2000
** eraRefco refraction constants for given ambient conditions
** eraApco astrometry parameters, ICRS-observed
** eraEors equation of the origins, given NPB matrix and s
**
** Copyright (C) 2013-2014, NumFOCUS Foundation.
** Derived, with permission, from the SOFA library. See notes at end of file.
*/
{
int j;
double tai1, tai2, tt1, tt2, ut11, ut12, ehpv[2][3], ebpv[2][3],
r[3][3], x, y, s, theta, sp, refa, refb;
/* UTC to other time scales. */
j = eraUtctai(utc1, utc2, &tai1, &tai2);
if ( j < 0 ) return -1;
j = eraTaitt(tai1, tai2, &tt1, &tt2);
j = eraUtcut1(utc1, utc2, dut1, &ut11, &ut12);
if ( j < 0 ) return -1;
/* Earth barycentric & heliocentric position/velocity (au, au/d). */
(void) eraEpv00(tt1, tt2, ehpv, ebpv);
/* Form the equinox based BPN matrix, IAU 2006/2000A. */
eraPnm06a(tt1, tt2, r);
/* Extract CIP X,Y. */
eraBpn2xy(r, &x, &y);
/* Obtain CIO locator s. */
s = eraS06(tt1, tt2, x, y);
/* Earth rotation angle. */
theta = eraEra00(ut11, ut12);
/* TIO locator s'. */
sp = eraSp00(tt1, tt2);
/* Refraction constants A and B. */
eraRefco(phpa, tc, rh, wl, &refa, &refb);
/* Compute the star-independent astrometry parameters. */
eraApco(tt1, tt2, ebpv, ehpv[0], x, y, s, theta,
elong, phi, hm, xp, yp, sp, refa, refb, astrom);
/* Equation of the origins. */
*eo = eraEors(r, s);
/* Return any warning status. */
return j;
/* Finished. */
}
/*----------------------------------------------------------------------
**
**
** Copyright (C) 2013-2014, 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.
**
*/