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slalib/rvlsrk.f

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+      REAL FUNCTION sla_RVLSRK (R2000, D2000)
+*+
+*     - - - - - - -
+*      R V L S R K
+*     - - - - - - -
+*
+*  Velocity component in a given direction due to the Sun's motion
+*  with respect to an adopted kinematic Local Standard of Rest.
+*
+*  (single precision)
+*
+*  Given:
+*     R2000,D2000   r    J2000.0 mean RA,Dec (radians)
+*
+*  Result:
+*     Component of "standard" solar motion in direction R2000,D2000 (km/s)
+*
+*  Sign convention:
+*     The result is +ve when the Sun is receding from the given point on
+*     the sky.
+*
+*  Note:  The Local Standard of Rest used here is one of several
+*         "kinematical" LSRs in common use.  A kinematical LSR is the
+*         mean standard of rest of specified star catalogues or stellar
+*         populations.  The Sun's motion with respect to a kinematical
+*         LSR is known as the "standard" solar motion.
+*
+*         There is another sort of LSR, the "dynamical" LSR, which is a
+*         point in the vicinity of the Sun which is in a circular orbit
+*         around the Galactic centre.  The Sun's motion with respect to
+*         the dynamical LSR is called the "peculiar" solar motion.  To
+*         obtain a radial velocity correction with respect to the
+*         dynamical LSR use the routine sla_RVLSRD.
+*
+*  Reference:  Delhaye (1965), in "Stars and Stellar Systems", vol 5,
+*              p73.
+*
+*  Called:
+*     sla_CS2C, sla_VDV
+*
+*  P.T.Wallace   Starlink   11 March 1994
+*
+*  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
+
+      REAL R2000,D2000
+
+      REAL VA(3), VB(3)
+
+      REAL sla_VDV
+
+*
+*  Standard solar motion (from Methods of Experimental Physics, ed Meeks,
+*  vol 12, part C, sec 6.1.5.2, p281):
+*
+*  20 km/s towards RA 18h Dec +30d (1900).
+*
+*  The solar motion is expressed here in the form of a J2000.0
+*  equatorial Cartesian vector:
+*
+*      VA(1) = X = -SPEED*COS(RA)*COS(DEC)
+*      VA(2) = Y = -SPEED*SIN(RA)*COS(DEC)
+*      VA(3) = Z = -SPEED*SIN(DEC)
+
+      DATA VA / -0.29000, +17.31726, -10.00141 /
+
+
+
+*  Convert given J2000 RA,Dec to x,y,z
+      CALL sla_CS2C(R2000,D2000,VB)
+
+*  Compute dot product with solar motion vector
+      sla_RVLSRK=sla_VDV(VA,VB)
+
+      END