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slalib/ecleq.f

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+      SUBROUTINE sla_ECLEQ (DL, DB, DATE, DR, DD)
+*+
+*     - - - - - -
+*      E C L E Q
+*     - - - - - -
+*
+*  Transformation from ecliptic coordinates to
+*  J2000.0 equatorial coordinates (double precision)
+*
+*  Given:
+*     DL,DB       dp      ecliptic longitude and latitude
+*                           (mean of date, IAU 1980 theory, radians)
+*     DATE        dp      TDB (loosely ET) as Modified Julian Date
+*                                              (JD-2400000.5)
+*  Returned:
+*     DR,DD       dp      J2000.0 mean RA,Dec (radians)
+*
+*  Called:
+*     sla_DCS2C, sla_ECMAT, sla_DIMXV, sla_PREC, sla_EPJ, sla_DCC2S,
+*     sla_DRANRM, sla_DRANGE
+*
+*  P.T.Wallace   Starlink   March 1986
+*
+*  Copyright (C) 1995 Rutherford Appleton Laboratory
+*
+*  License:
+*    This program is free software; you can redistribute it and/or modify
+*    it under the terms of the GNU General Public License as published by
+*    the Free Software Foundation; either version 2 of the License, or
+*    (at your option) any later version.
+*
+*    This program is distributed in the hope that it will be useful,
+*    but WITHOUT ANY WARRANTY; without even the implied warranty of
+*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+*    GNU General Public License for more details.
+*
+*    You should have received a copy of the GNU General Public License
+*    along with this program (see SLA_CONDITIONS); if not, write to the 
+*    Free Software Foundation, Inc., 59 Temple Place, Suite 330, 
+*    Boston, MA  02111-1307  USA
+*
+*-
+
+      IMPLICIT NONE
+
+      DOUBLE PRECISION DL,DB,DATE,DR,DD
+
+      DOUBLE PRECISION sla_EPJ,sla_DRANRM,sla_DRANGE
+
+      DOUBLE PRECISION RMAT(3,3),V1(3),V2(3)
+
+
+
+*  Spherical to Cartesian
+      CALL sla_DCS2C(DL,DB,V1)
+
+*  Ecliptic to equatorial
+      CALL sla_ECMAT(DATE,RMAT)
+      CALL sla_DIMXV(RMAT,V1,V2)
+
+*  Mean of date to J2000
+      CALL sla_PREC(2000D0,sla_EPJ(DATE),RMAT)
+      CALL sla_DIMXV(RMAT,V2,V1)
+
+*  Cartesian to spherical
+      CALL sla_DCC2S(V1,DR,DD)
+
+*  Express in conventional ranges
+      DR=sla_DRANRM(DR)
+      DD=sla_DRANGE(DD)
+
+      END