SUBROUTINE sla_SUBET (RC, DC, EQ, RM, DM) *+ * - - - - - - * S U B E T * - - - - - - * * Remove the E-terms (elliptic component of annual aberration) * from a pre IAU 1976 catalogue RA,Dec to give a mean place * (double precision) * * Given: * RC,DC dp RA,Dec (radians) with E-terms included * EQ dp Besselian epoch of mean equator and equinox * * Returned: * RM,DM dp RA,Dec (radians) without E-terms * * Called: * sla_ETRMS, sla_DCS2C, sla_,DVDV, sla_DCC2S, sla_DRANRM * * Explanation: * Most star positions from pre-1984 optical catalogues (or * derived from astrometry using such stars) embody the * E-terms. This routine converts such a position to a * formal mean place (allowing, for example, comparison with a * pulsar timing position). * * Reference: * Explanatory Supplement to the Astronomical Ephemeris, * section 2D, page 48. * * P.T.Wallace Starlink 10 May 1990 * * 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 RC,DC,EQ,RM,DM DOUBLE PRECISION sla_DRANRM,sla_DVDV DOUBLE PRECISION A(3),V(3),F INTEGER I * E-terms CALL sla_ETRMS(EQ,A) * Spherical to Cartesian CALL sla_DCS2C(RC,DC,V) * Include the E-terms F=1D0+sla_DVDV(V,A) DO I=1,3 V(I)=F*V(I)-A(I) END DO * Cartesian to spherical CALL sla_DCC2S(V,RM,DM) * Bring RA into conventional range RM=sla_DRANRM(RM) END