SUBROUTINE iau_JD2CAL ( DJ1, DJ2, IY, IM, ID, FD, J ) *+ * - - - - - - - - - - - * i a u _ J D 2 C A L * - - - - - - - - - - - * * Julian Date to Gregorian year, month, day, and fraction of a day. * * This routine is part of the International Astronomical Union's * SOFA (Standards of Fundamental Astronomy) software collection. * * Status: support routine. * * Given: * DJ1,DJ2 d Julian Date (Notes 1, 2) * * Returned: * IY i year * IM i month * ID i day * FD d fraction of day * J i status: * 0 = OK * -1 = unacceptable date (Note 3) * * Notes: * * 1) The earliest valid date is -68569.5 (-4900 March 1). The * largest value accepted is 10^9. * * 2) The Julian Date is apportioned in any convenient way between * the arguments DJ1 and DJ2. For example, JD=2450123.7 could * be expressed in any of these ways, among others: * * DJ1 DJ2 * * 2450123.7D0 0D0 (JD method) * 2451545D0 -1421.3D0 (J2000 method) * 2400000.5D0 50123.2D0 (MJD method) * 2450123.5D0 0.2D0 (date & time method) * * 3) In early eras the conversion is from the "Proleptic Gregorian * Calendar"; no account is taken of the date(s) of adoption of * the Gregorian Calendar, nor is the AD/BC numbering convention * observed. * * Reference: * * Explanatory Supplement to the Astronomical Almanac, * P. Kenneth Seidelmann (ed), University Science Books (1992), * Section 12.92 (p604). * * This revision: 2007 October 16 * * Copyright (C) 2008 IAU SOFA Review Board. See notes at end. * *----------------------------------------------------------------------- IMPLICIT NONE DOUBLE PRECISION DJ1, DJ2 INTEGER IY, IM, ID DOUBLE PRECISION FD INTEGER J * Minimum and maximum allowed JD DOUBLE PRECISION DJMIN, DJMAX PARAMETER ( DJMIN = -68569.5D0, DJMAX = 1D9 ) INTEGER JD, L, N, I, K DOUBLE PRECISION DJ, D1, D2, F1, F2, F, D * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - * Check if date is acceptable. DJ = DJ1 + DJ2 IF ( DJ.LT.DJMIN .OR. DJ.GT.DJMAX ) THEN J = -1 ELSE J = 0 * Copy the date, big then small, and re-align to midnight. IF ( DJ1 .GE. DJ2 ) THEN D1 = DJ1 D2 = DJ2 ELSE D1 = DJ2 D2 = DJ1 END IF D2 = D2 - 0.5D0 * Separate day and fraction. F1 = MOD(D1,1D0) F2 = MOD(D2,1D0) F = MOD(F1+F2,1D0) IF ( F .LT. 0D0 ) F = F+1D0 D = ANINT(D1-F1) + ANINT(D2-F2) + ANINT(F1+F2-F) JD = NINT(D) + 1 * Express day in Gregorian calendar. L = JD + 68569 N = ( 4*L ) / 146097 L = L - ( 146097*N + 3 ) / 4 I = ( 4000 * (L+1) ) / 1461001 L = L - ( 1461*I ) / 4 + 31 K = ( 80*L ) / 2447 ID = L - ( 2447*K ) / 80 L = K / 11 IM = K + 2 - 12*L IY = 100 * ( N-49 ) + I + L FD = F END IF * Finished. *+----------------------------------------------------------------------- * * Copyright (C) 2008 * Standards Of Fundamental Astronomy Review Board * of the International Astronomical Union. * * ===================== * SOFA Software License * ===================== * * NOTICE TO USER: * * BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING TERMS AND CONDITIONS * WHICH APPLY TO ITS USE. * * 1. The Software is owned by the IAU SOFA Review Board ("the Board"). * * 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 adapt the SOFA software and its * algorithms for your own purposes and you may copy and distribute * a resulting "derived work" to others on a world-wide, royalty-free * basis, provided that the derived work complies 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 contain * software provided by SOFA or software that has been distributed * by or endorsed by SOFA. * * b) The source code of your derived work must contain descriptions * of how the derived work is based upon and/or differs from the * original SOFA software. * * c) The name(s) of all routine(s) that you distribute shall differ * from the SOFA names, even when the SOFA content has not been * otherwise changed. * * d) The routine-naming prefix "iau" shall not be used. * * e) 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. * * f) 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. * * 4. In any published work or commercial products which includes * results achieved by using the SOFA software, you shall acknowledge * that the SOFA software was used in obtaining those results. * * 5. You shall not cause the SOFA software to be brought into * disrepute, either by misuse, or use for inappropriate tasks, or by * inappropriate modification. * * 6. The SOFA software is provided "as is" and the Board makes no * warranty as to its use or performance. The Board does not and * cannot warrant the performance or results which the user may obtain * by using the SOFA software. The Board 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 the Board be liable to the user for any consequential, * incidental, or special damages, including any lost profits or lost * savings, even if a Board representative has been advised of such * damages, or for any claim by any third party. * * 7. 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. * * Correspondence concerning SOFA software should be addressed as * follows: * * Internet email: sofa@rl.ac.uk * Postal address: IAU SOFA Center * Rutherford Appleton Laboratory * Chilton, Didcot, Oxon OX11 0QX * United Kingdom * *----------------------------------------------------------------------- END