SUBROUTINE iau_ATCIQZ ( RC, DC, ASTROM, RI, DI )
*+
* - - - - - - - - - - -
* i a u _ A T C I Q Z
* - - - - - - - - - - -
*
* Quick ICRS to CIRS transformation, given precomputed star-independent
* astrometry parameters, and assuming zero parallax and proper motion.
*
* Use of this routine is appropriate when efficiency is important and
* where many star positions are to be transformed for one date. The
* star-independent parameters can be obtained by calling one of the
* routines iau_APCI[13], iau_APCG[13], iau_APCO[13] or iau_APCS[13].
*
* The corresponding routine for the case of non-zero parallax and
* proper motion is iau_ATCIQ.
*
* This routine is part of the International Astronomical Union's
* SOFA (Standards of Fundamental Astronomy) software collection.
*
* Status: support routine.
*
* Given:
* RC,DC d ICRS astrometric RA,Dec (radians)
* ASTROM d(30) star-independent astrometry parameters:
* (1) PM time interval (SSB, Julian years)
* (2-4) SSB to observer (vector, au)
* (5-7) Sun to observer (unit vector)
* (8) distance from Sun to observer (au)
* (9-11) v: barycentric observer velocity (vector, c)
* (12) sqrt(1-|v|^2): reciprocal of Lorenz factor
* (13-21) bias-precession-nutation matrix
* (22) longitude + s' (radians)
* (23) polar motion xp wrt local meridian (radians)
* (24) polar motion yp wrt local meridian (radians)
* (25) sine of geodetic latitude
* (26) cosine of geodetic latitude
* (27) magnitude of diurnal aberration vector
* (28) "local" Earth rotation angle (radians)
* (29) refraction constant A (radians)
* (30) refraction constant B (radians)
*
* Returned:
* RI,DI d CIRS RA,Dec (radians)
*
* Note:
*
* All the vectors are with respect to BCRS axes.
*
* References:
*
* Urban, S. & Seidelmann, P. K. (eds), Explanatory Supplement to
* the Astronomical Almanac, 3rd ed., University Science Books
* (2013).
*
* Klioner, Sergei A., "A practical relativistic model for micro-
* arcsecond astrometry in space", Astr. J. 125, 1580-1597 (2003).
*
* Called:
* iau_S2C spherical coordinates to unit vector
* iau_LDSUN light deflection due to Sun
* iau_AB stellar aberration
* iau_RXP product of r-matrix and p-vector
* iau_C2S p-vector to spherical
* iau_ANP normalize angle into range +/- pi
*
* This revision: 2013 August 31
*
* SOFA release 2021-05-12
*
* Copyright (C) 2021 IAU SOFA Board. See notes at end.
*
*-----------------------------------------------------------------------
IMPLICIT NONE
DOUBLE PRECISION RC, DC, ASTROM(30), RI, DI
DOUBLE PRECISION PCO(3), PNAT(3), PPR(3), PI(3), W
DOUBLE PRECISION iau_ANP
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
* BCRS coordinate direction (unit vector).
CALL iau_S2C ( RC, DC, PCO )
* Light deflection by the Sun, giving BCRS natural direction.
CALL iau_LDSUN ( PCO, ASTROM(5), ASTROM(8), PNAT )
* Aberration, giving GCRS proper direction.
CALL iau_AB ( PNAT, ASTROM(9), ASTROM(8), ASTROM(12), PPR )
* Bias-precession-nutation, giving CIRS proper direction.
CALL iau_RXP ( ASTROM(13), PPR, PI )
* CIRS RA,Dec.
CALL iau_C2S ( PI, W, DI )
RI = iau_ANP ( W )
* Finished.
*+----------------------------------------------------------------------
*
* Copyright (C) 2021
* Standards Of Fundamental Astronomy Board
* of the International Astronomical Union.
*
* =====================
* SOFA Software License
* =====================
*
* NOTICE TO USER:
*
* BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING SIX TERMS AND
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*
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*
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*
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*
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*
*-----------------------------------------------------------------------
END