int iauAtoc13(const char *type, double ob1, double ob2,
double utc1, double utc2, double dut1,
double elong, double phi, double hm, double xp, double yp,
double phpa, double tc, double rh, double wl,
double *rc, double *dc)
/*
** - - - - - - - - - -
** i a u A t o c 1 3
** - - - - - - - - - -
**
** Observed place at a groundbased site to to ICRS astrometric RA,Dec.
** The caller supplies UTC, site coordinates, ambient air conditions
** and observing wavelength.
**
** This function is part of the International Astronomical Union's
** SOFA (Standards of Fundamental Astronomy) software collection.
**
** Status: support function.
**
** Given:
** type char[] type of coordinates - "R", "H" or "A" (Notes 1,2)
** ob1 double observed Az, HA or RA (radians; Az is N=0,E=90)
** ob2 double observed ZD or Dec (radians)
** utc1 double UTC as a 2-part...
** utc2 double ...quasi Julian Date (Notes 3,4)
** dut1 double UT1-UTC (seconds, Note 5)
** elong double longitude (radians, east +ve, Note 6)
** phi double geodetic latitude (radians, Note 6)
** hm double height above ellipsoid (m, geodetic Notes 6,8)
** xp,yp double polar motion coordinates (radians, Note 7)
** phpa double pressure at the observer (hPa = mB, Note 8)
** tc double ambient temperature at the observer (deg C)
** rh double relative humidity at the observer (range 0-1)
** wl double wavelength (micrometers, Note 9)
**
** Returned:
** rc,dc double ICRS astrometric RA,Dec (radians)
**
** Returned (function value):
** int status: +1 = dubious year (Note 4)
** 0 = OK
** -1 = unacceptable date
**
** Notes:
**
** 1) "Observed" Az,ZD means the position that would be seen by a
** perfect geodetically aligned theodolite. (Zenith distance is
** used rather than altitude in order to reflect the fact that no
** allowance is made for depression of the horizon.) This is
** related to the observed HA,Dec via the standard rotation, using
** the geodetic latitude (corrected for polar motion), while the
** observed HA and RA are related simply through the Earth rotation
** angle and the site longitude. "Observed" RA,Dec or HA,Dec thus
** means the position that would be seen by a perfect equatorial
** with its polar axis aligned to the Earth's axis of rotation.
**
** 2) Only the first character of the type argument is significant.
** "R" or "r" indicates that ob1 and ob2 are the observed right
** ascension and declination; "H" or "h" indicates that they are
** hour angle (west +ve) and declination; anything else ("A" or
** "a" is recommended) indicates that ob1 and ob2 are azimuth
** (north zero, east 90 deg) and zenith distance.
**
** 3) 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 iauDtf2d 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.
**
** 4) 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 iauDat for further details.
**
** 5) 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.
**
** 6) The geographical coordinates are with respect to the 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.
**
** 7) 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.
**
** 8) 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.
**
** 9) 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).
**
** 10) The accuracy of the result is limited by the corrections for
** refraction, which use a simple A*tan(z) + B*tan^3(z) model.
** Providing the meteorological parameters are known accurately and
** there are no gross local effects, the predicted astrometric
** coordinates should be within 0.05 arcsec (optical) or 1 arcsec
** (radio) for a zenith distance of less than 70 degrees, better
** than 30 arcsec (optical or radio) at 85 degrees and better
** than 20 arcmin (optical) or 30 arcmin (radio) at the horizon.
**
** Without refraction, the complementary functions iauAtco13 and
** iauAtoc13 are self-consistent to better than 1 microarcsecond
** all over the celestial sphere. With refraction included,
** consistency falls off at high zenith distances, but is still
** better than 0.05 arcsec at 85 degrees.
**
** 11) 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.
**
** Called:
** iauApco13 astrometry parameters, ICRS-observed
** iauAtoiq quick observed to CIRS
** iauAticq quick CIRS to ICRS
**
** This revision: 2013 October 9
**
** SOFA release 2015-02-09
**
** Copyright (C) 2015 IAU SOFA Board. See notes at end.
*/
{
int j;
iauASTROM astrom;
double eo, ri, di;
/* Star-independent astrometry parameters. */
j = iauApco13(utc1, utc2, dut1, elong, phi, hm, xp, yp,
phpa, tc, rh, wl, &astrom, &eo);
/* Abort if bad UTC. */
if ( j < 0 ) return j;
/* Transform observed to CIRS. */
iauAtoiq(type, ob1, ob2, &astrom, &ri, &di);
/* Transform CIRS to ICRS. */
iauAticq(ri, di, &astrom, rc, dc);
/* Return OK/warning status. */
return j;
/* Finished. */
/*----------------------------------------------------------------------
**
** Copyright (C) 2015
** 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
** CONDITIONS WHICH APPLY TO ITS USE.
**
** 1. The Software is owned by the IAU SOFA Board ("SOFA").
**
** 2. Permission is granted to anyone to use the SOFA software for any
** purpose, including commercial applications, free of charge and
** without payment of royalties, subject to the conditions and
** restrictions listed below.
**
** 3. You (the user) may copy and distribute SOFA source code to others,
** and use and adapt its code and algorithms in your own software,
** on a world-wide, royalty-free basis. That portion of your
** distribution that does not consist of intact and unchanged copies
** of SOFA source code files is a "derived work" that must comply
** with the following requirements:
**
** a) Your work shall be marked or carry a statement that it
** (i) uses routines and computations derived by you from
** software provided by SOFA under license to you; and
** (ii) does not itself constitute software provided by and/or
** endorsed by SOFA.
**
** b) The source code of your derived work must contain descriptions
** of how the derived work is based upon, contains and/or differs
** from the original SOFA software.
**
** c) The names of all routines in your derived work shall not
** include the prefix "iau" or "sofa" or trivial modifications
** thereof such as changes of case.
**
** d) The origin of the SOFA components of your derived work must
** not be misrepresented; you must not claim that you wrote the
** original software, nor file a patent application for SOFA
** software or algorithms embedded in the SOFA software.
**
** e) These requirements must be reproduced intact in any source
** distribution and shall apply to anyone to whom you have
** granted a further right to modify the source code of your
** derived work.
**
** Note that, as originally distributed, the SOFA software is
** intended to be a definitive implementation of the IAU standards,
** and consequently third-party modifications are discouraged. All
** variations, no matter how minor, must be explicitly marked as
** such, as explained above.
**
** 4. You shall not cause the SOFA software to be brought into
** disrepute, either by misuse, or use for inappropriate tasks, or
** by inappropriate modification.
**
** 5. The SOFA software is provided "as is" and SOFA makes no warranty
** as to its use or performance. SOFA does not and cannot warrant
** the performance or results which the user may obtain by using the
** SOFA software. SOFA makes no warranties, express or implied, as
** to non-infringement of third party rights, merchantability, or
** fitness for any particular purpose. In no event will SOFA be
** liable to the user for any consequential, incidental, or special
** damages, including any lost profits or lost savings, even if a
** SOFA representative has been advised of such damages, or for any
** claim by any third party.
**
** 6. The provision of any version of the SOFA software under the terms
** and conditions specified herein does not imply that future
** versions will also be made available under the same terms and
** conditions.
*
** In any published work or commercial product which uses the SOFA
** software directly, acknowledgement (see www.iausofa.org) is
** appreciated.
**
** Correspondence concerning SOFA software should be addressed as
** follows:
**
** By email: [email protected]
** By post: IAU SOFA Center
** HM Nautical Almanac Office
** UK Hydrographic Office
** Admiralty Way, Taunton
** Somerset, TA1 2DN
** United Kingdom
**
**--------------------------------------------------------------------*/
}
void iauAtic13(double ri, double di, double date1, double date2,
double *rc, double *dc, double *eo)
/*
** - - - - - - - - - -
** i a u A t i c 1 3
** - - - - - - - - - -
**
** Transform star RA,Dec from geocentric CIRS to ICRS astrometric.
**
** This function is part of the International Astronomical Union's
** SOFA (Standards of Fundamental Astronomy) software collection.
**
** Status: support function.
**
** Given:
** ri,di double CIRS geocentric RA,Dec (radians)
** date1 double TDB as a 2-part...
** date2 double ...Julian Date (Note 1)
**
** Returned:
** rc,dc double ICRS astrometric RA,Dec (radians)
** eo double equation of the origins (ERA-GST, Note 4)
**
** Notes:
**
** 1) The TDB date date1+date2 is a Julian Date, apportioned in any
** convenient way between the two arguments. For example,
** JD(TDB)=2450123.7 could be expressed in any of these ways, among
** others:
**
** date1 date2
**
** 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
** resolution. The MJD method and the date & time methods are both
** good compromises between resolution and convenience. For most
** applications of this function the choice will not be at all
** critical.
**
** TT can be used instead of TDB without any significant impact on
** accuracy.
**
** 2) Iterative techniques are used for the aberration and light
** deflection corrections so that the functions iauAtic13 (or
** iauAticq) and iauAtci13 (or iauAtciq) are accurate inverses;
** even at the edge of the Sun's disk the discrepancy is only about
** 1 nanoarcsecond.
**
** 3) The available accuracy is better than 1 milliarcsecond, limited
** mainly by the precession-nutation model that is used, namely
** IAU 2000A/2006. Very close to solar system bodies, additional
** errors of up to several milliarcseconds can occur because of
** unmodeled light deflection; however, the Sun's contribution is
** taken into account, to first order. The accuracy limitations of
** the SOFA function iauEpv00 (used to compute Earth position and
** velocity) can contribute aberration errors of up to
** 5 microarcseconds. Light deflection at the Sun's limb is
** uncertain at the 0.4 mas level.
**
** 4) Should the transformation to (equinox based) J2000.0 mean place
** be required rather than (CIO based) ICRS coordinates, subtract the
** equation of the origins from the returned right ascension:
** RA = RI - EO. (The iauAnp function can then be applied, as
** required, to keep the result in the conventional 0-2pi range.)
**
** Called:
** iauApci13 astrometry parameters, ICRS-CIRS, 2013
** iauAticq quick CIRS to ICRS astrometric
**
** This revision: 2013 October 9
**
** SOFA release 2016-05-03
**
** Copyright (C) 2016 IAU SOFA Board. See notes at end.
*/
{
/* Star-independent astrometry parameters */
iauASTROM astrom;
/* Star-independent astrometry parameters. */
iauApci13(date1, date2, &astrom, eo);
/* CIRS to ICRS astrometric. */
iauAticq(ri, di, &astrom, rc, dc);
/* Finished. */
/*----------------------------------------------------------------------
**
** Copyright (C) 2016
** 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
** CONDITIONS WHICH APPLY TO ITS USE.
**
** 1. The Software is owned by the IAU SOFA Board ("SOFA").
**
** 2. Permission is granted to anyone to use the SOFA software for any
** purpose, including commercial applications, free of charge and
** without payment of royalties, subject to the conditions and
** restrictions listed below.
**
** 3. You (the user) may copy and distribute SOFA source code to others,
** and use and adapt its code and algorithms in your own software,
** on a world-wide, royalty-free basis. That portion of your
** distribution that does not consist of intact and unchanged copies
** of SOFA source code files is a "derived work" that must comply
** with the following requirements:
**
** a) Your work shall be marked or carry a statement that it
** (i) uses routines and computations derived by you from
** software provided by SOFA under license to you; and
** (ii) does not itself constitute software provided by and/or
** endorsed by SOFA.
**
** b) The source code of your derived work must contain descriptions
** of how the derived work is based upon, contains and/or differs
** from the original SOFA software.
**
** c) The names of all routines in your derived work shall not
** include the prefix "iau" or "sofa" or trivial modifications
** thereof such as changes of case.
**
** d) The origin of the SOFA components of your derived work must
** not be misrepresented; you must not claim that you wrote the
** original software, nor file a patent application for SOFA
** software or algorithms embedded in the SOFA software.
**
** e) These requirements must be reproduced intact in any source
** distribution and shall apply to anyone to whom you have
** granted a further right to modify the source code of your
** derived work.
**
** Note that, as originally distributed, the SOFA software is
** intended to be a definitive implementation of the IAU standards,
** and consequently third-party modifications are discouraged. All
** variations, no matter how minor, must be explicitly marked as
** such, as explained above.
**
** 4. You shall not cause the SOFA software to be brought into
** disrepute, either by misuse, or use for inappropriate tasks, or
** by inappropriate modification.
**
** 5. The SOFA software is provided "as is" and SOFA makes no warranty
** as to its use or performance. SOFA does not and cannot warrant
** the performance or results which the user may obtain by using the
** SOFA software. SOFA makes no warranties, express or implied, as
** to non-infringement of third party rights, merchantability, or
** fitness for any particular purpose. In no event will SOFA be
** liable to the user for any consequential, incidental, or special
** damages, including any lost profits or lost savings, even if a
** SOFA representative has been advised of such damages, or for any
** claim by any third party.
**
** 6. The provision of any version of the SOFA software under the terms
** and conditions specified herein does not imply that future
** versions will also be made available under the same terms and
** conditions.
*
** In any published work or commercial product which uses the SOFA
** software directly, acknowledgement (see www.iausofa.org) is
** appreciated.
**
** Correspondence concerning SOFA software should be addressed as
** follows:
**
** By email: [email protected]
** By post: IAU SOFA Center
** HM Nautical Almanac Office
** UK Hydrographic Office
** Admiralty Way, Taunton
** Somerset, TA1 2DN
** United Kingdom
**
**--------------------------------------------------------------------*/
}
