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authorJoseph Hunkeler <jhunkeler@gmail.com>2015-03-04 21:21:30 -0500
committerJoseph Hunkeler <jhunkeler@gmail.com>2015-03-04 21:21:30 -0500
commitd54fe7c1f704a63824c5bfa0ece65245572e9b27 (patch)
treeafc52015ffc2c74e0266653eecef1c8ef8ba5d91 /src/slalib/eg50.f
downloadcalfuse-d54fe7c1f704a63824c5bfa0ece65245572e9b27.tar.gz
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+ SUBROUTINE sla_EG50 (DR, DD, DL, DB)
+*+
+* - - - - -
+* E G 5 0
+* - - - - -
+*
+* Transformation from B1950.0 'FK4' equatorial coordinates to
+* IAU 1958 galactic coordinates (double precision)
+*
+* Given:
+* DR,DD dp B1950.0 'FK4' RA,Dec
+*
+* Returned:
+* DL,DB dp galactic longitude and latitude L2,B2
+*
+* (all arguments are radians)
+*
+* Called:
+* sla_DCS2C, sla_DMXV, sla_DCC2S, sla_SUBET, sla_DRANRM, sla_DRANGE
+*
+* Note:
+* The equatorial coordinates are B1950.0 'FK4'. Use the
+* routine sla_EQGAL if conversion from J2000.0 coordinates
+* is required.
+*
+* Reference:
+* Blaauw et al, Mon.Not.R.Astron.Soc.,121,123 (1960)
+*
+* P.T.Wallace Starlink 5 September 1993
+*
+* Copyright (C) 1995 Rutherford Appleton Laboratory
+*-
+
+ IMPLICIT NONE
+
+ DOUBLE PRECISION DR,DD,DL,DB
+
+ DOUBLE PRECISION sla_DRANRM,sla_DRANGE
+
+ DOUBLE PRECISION V1(3),V2(3),R,D
+
+*
+* 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
+*
+* The Euler angles are P, Q, 90-R, about the z then y then
+* z axes.
+*
+* +CP.CQ.SR-SP.CR +SP.CQ.SR+CP.CR -SQ.SR
+*
+* -CP.CQ.CR-SP.SR -SP.CQ.CR+CP.SR +SQ.CR
+*
+* +CP.SQ +SP.SQ +CQ
+*
+
+ 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) /
+ : -0.066988739415D0,-0.872755765852D0,-0.483538914632D0,
+ : +0.492728466075D0,-0.450346958020D0,+0.744584633283D0,
+ : -0.867600811151D0,-0.188374601723D0,+0.460199784784D0 /
+
+
+
+* Remove E-terms
+ CALL sla_SUBET(DR,DD,1950D0,R,D)
+
+* Spherical to Cartesian
+ CALL sla_DCS2C(R,D,V1)
+
+* Rotate to galactic
+ CALL sla_DMXV(RMAT,V1,V2)
+
+* Cartesian to spherical
+ CALL sla_DCC2S(V2,DL,DB)
+
+* Express angles in conventional ranges
+ DL=sla_DRANRM(DL)
+ DB=sla_DRANGE(DB)
+
+ END