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: 2001 September 16 * * Copyright (C) 2003 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 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 J = ( 80*L ) / 2447 ID = L - ( 2447*J ) / 80 L = J / 11 IM = J + 2 - 12*L IY = 100 * ( N-49 ) + I + L FD = F J = 0 END IF * Finished. *+---------------------------------------------------------------------- * * Copyright (C) 2003 * 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. The Software is made available free of charge for use by: * * a) private individuals for non-profit research; and * * b) non-profit educational, academic and research institutions. * * 3. Commercial use of the Software is specifically excluded from the * terms and conditions of this license. Commercial use of the * Software is subject to the prior written agreement of the Board on * terms to be agreed. * * 4. The provision of any version of the 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. * * 5. The user may modify the Software for his/her own purposes. The * user may distribute the modified software provided that the Board * is informed and that a copy of the modified software is made * available to the Board on request. All modifications made by the * user shall be clearly identified to show how the modified software * differs from the original Software, and the name(s) of the * affected routine(s) shall be changed. The original SOFA Software * License text must be present. * * 6. In any published work produced by the user and which includes * results achieved by using the Software, the user shall acknowledge * that the Software was used in producing the information contained * in such publication. * * 7. The user may incorporate or embed the Software into other software * products which he/she may then give away free of charge but not * sell provided the user makes due acknowledgement of the use which * he/she has made of the Software in creating such software * products. Any redistribution of the Software in this way shall be * made under the same terms and conditions under which the user * received it from the SOFA Center. * * 8. The user shall not cause the Software to be brought into * disrepute, either by misuse, or use for inappropriate tasks, or by * inappropriate modification. * * 9. The Software is provided to the user "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 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. * * 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