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Diffstat (limited to 'math/slalib/galeq.f')
| -rw-r--r-- | math/slalib/galeq.f | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/math/slalib/galeq.f b/math/slalib/galeq.f new file mode 100644 index 00000000..e0010c8b --- /dev/null +++ b/math/slalib/galeq.f @@ -0,0 +1,97 @@ + SUBROUTINE slGAEQ (DL, DB, DR, DD) +*+ +* - - - - - - +* G A E Q +* - - - - - - +* +* Transformation from IAU 1958 galactic coordinates to +* J2000.0 equatorial coordinates (double precision) +* +* Given: +* DL,DB dp galactic longitude and latitude L2,B2 +* +* Returned: +* DR,DD dp J2000.0 RA,Dec +* +* (all arguments are radians) +* +* Called: +* slDS2C, slDIMV, slDC2S, slDA2P, slDA1P +* +* Note: +* The equatorial coordinates are J2000.0. Use the routine +* slGE50 if conversion to B1950.0 'FK4' coordinates is +* required. +* +* Reference: +* Blaauw et al, Mon.Not.R.Astron.Soc.,121,123 (1960) +* +* P.T.Wallace Starlink 21 September 1998 +* +* Copyright (C) 1998 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., 51 Franklin Street, Fifth Floor, +* Boston, MA 02110-1301 USA +* +* Copyright (C) 1995 Association of Universities for Research in Astronomy Inc. +*- + + IMPLICIT NONE + + DOUBLE PRECISION DL,DB,DR,DD + + DOUBLE PRECISION slDA2P,slDA1P + + DOUBLE PRECISION V1(3),V2(3) + +* +* L2,B2 system of galactic coordinates +* +* P = 192.25 RA of galactic north pole (mean B1950.0) +* Q = 62.6 inclination of galactic to mean B1950.0 equator +* R = 33 longitude of ascending node +* +* P,Q,R are degrees +* +* Equatorial to galactic rotation matrix (J2000.0), obtained by +* applying the standard FK4 to FK5 transformation, for zero proper +* motion in FK5, to the columns of the B1950 equatorial to +* galactic rotation matrix: +* + DOUBLE PRECISION RMAT(3,3) + DATA RMAT(1,1),RMAT(1,2),RMAT(1,3), + : RMAT(2,1),RMAT(2,2),RMAT(2,3), + : RMAT(3,1),RMAT(3,2),RMAT(3,3)/ + : -0.054875539726D0,-0.873437108010D0,-0.483834985808D0, + : +0.494109453312D0,-0.444829589425D0,+0.746982251810D0, + : -0.867666135858D0,-0.198076386122D0,+0.455983795705D0/ + + + +* Spherical to Cartesian + CALL slDS2C(DL,DB,V1) + +* Galactic to equatorial + CALL slDIMV(RMAT,V1,V2) + +* Cartesian to spherical + CALL slDC2S(V2,DR,DD) + +* Express in conventional ranges + DR=slDA2P(DR) + DD=slDA1P(DD) + + END |