SUBROUTINE iau_UTCUT1 ( UTC1, UTC2, DUT1, UT11, UT12, J )
*+
* - - - - - - - - - - -
* i a u _ U T C U T 1
* - - - - - - - - - - -
*
* Time scale transformation: Coordinated Universal Time, UTC, to
* Universal Time, UT1.
*
* This routine is part of the International Astronomical Union's
* SOFA (Standards of Fundamental Astronomy) software collection.
*
* Status: canonical.
*
* Given:
* UTC1,UTC2 d UTC as a 2-part quasi Julian Date (Notes 1-4)
* DUT1 d Delta UT1 = UT1-UTC in seconds (Note 5)
*
* Returned:
* UT11,UT12 d UT1 as a 2-part Julian Date (Note 6)
* J i status: +1 = dubious year (Note 3)
* 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.
*
* 2) JD cannot unambiguously represent UTC during a leap second unless
* special measures are taken. The convention in the present routine
* is that the JD day represents UTC days whether the length is
* 86399, 86400 or 86401 SI seconds.
*
* 3) 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 iau_DAT for further details.
*
* 4) The routine iau_DTF2D converts from calendar date and time of day
* into 2-part Julian Date, and in the case of UTC implements the
* leap-second-ambiguity convention described above.
*
* 5) Delta UT1 can be obtained from tabulations provided by the
* International Earth Rotation and Reference Systems Service.
* It is the caller's responsibility to supply a DUT1 argument
* containing the UT1-UTC value that matches the given UTC.
*
* 6) The returned UT11,UT12 are such that their sum is the UT1 Julian
* Date.
*
* References:
*
* McCarthy, D. D., Petit, G. (eds.), IERS Conventions (2003),
* IERS Technical Note No. 32, BKG (2004)
*
* Explanatory Supplement to the Astronomical Almanac,
* P. Kenneth Seidelmann (ed), University Science Books (1992)
*
* Called:
* iau_JD2CAL JD to Gregorian calendar
* iau_DAT delta(AT) = TAI-UTC
* iau_UTCTAI UTC to TAI
* iau_TAIUT1 TAI to UT1
*
* This revision: 2013 August 12
*
* SOFA release 2017-04-20
*
* Copyright (C) 2017 IAU SOFA Board. See notes at end.
*
*-----------------------------------------------------------------------
IMPLICIT NONE
DOUBLE PRECISION UTC1, UTC2, DUT1, UT11, UT12
INTEGER J
INTEGER IY, IM, ID, JS, JW
DOUBLE PRECISION W, DAT, DTA, TAI1, TAI2
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
* Look up TAI-UTC.
CALL iau_JD2CAL ( UTC1, UTC2, IY, IM, ID, W, JS )
IF ( JS.NE.0 ) GO TO 9
CALL iau_DAT ( IY, IM, ID, 0D0, DAT, JS )
IF ( JS.LT.0 ) GO TO 9
* Form UT1-TAI.
DTA = DUT1 - DAT
* UTC to TAI to UT1.
CALL iau_UTCTAI ( UTC1, UTC2, TAI1, TAI2, JW )
IF ( JW.LT.0 ) THEN
JS = JW
GO TO 9
END IF
CALL iau_TAIUT1 ( TAI1, TAI2, DTA, UT11, UT12, JW )
* Return the status.
9 CONTINUE
J = JS
* Finished.
*+----------------------------------------------------------------------
*
* Copyright (C) 2017
* 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
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* 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
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*
* 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: sofa@ukho.gov.uk
* By post: IAU SOFA Center
* HM Nautical Almanac Office
* UK Hydrographic Office
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*
*-----------------------------------------------------------------------
END