From d54fe7c1f704a63824c5bfa0ece65245572e9b27 Mon Sep 17 00:00:00 2001 From: Joseph Hunkeler Date: Wed, 4 Mar 2015 21:21:30 -0500 Subject: Initial commit --- src/slalib/rvlsrd.f | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) create mode 100644 src/slalib/rvlsrd.f (limited to 'src/slalib/rvlsrd.f') diff --git a/src/slalib/rvlsrd.f b/src/slalib/rvlsrd.f new file mode 100644 index 0000000..96f90c9 --- /dev/null +++ b/src/slalib/rvlsrd.f @@ -0,0 +1,78 @@ + REAL FUNCTION sla_RVLSRD (R2000, D2000) +*+ +* - - - - - - - +* R V L S R D +* - - - - - - - +* +* Velocity component in a given direction due to the Sun's motion +* with respect to the dynamical Local Standard of Rest. +* +* (single precision) +* +* Given: +* R2000,D2000 r J2000.0 mean RA,Dec (radians) +* +* Result: +* Component of "peculiar" 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 the "dynamical" LSR, +* 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. +* +* There is another type of LSR, called a "kinematical" LSR. A +* kinematical LSR is the mean standard of rest of specified star +* catalogues or stellar populations, and several slightly +* different kinematical LSRs are in use. The Sun's motion with +* respect to an agreed kinematical LSR is known as the "standard" +* solar motion. To obtain a radial velocity correction with +* respect to an adopted kinematical LSR use the routine sla_RVLSRK. +* +* Reference: Delhaye (1965), in "Stars and Stellar Systems", vol 5, +* p73. +* +* Called: +* sla_CS2C, sla_VDV +* +* P.T.Wallace Starlink 9 March 1994 +* +* Copyright (C) 1995 Rutherford Appleton Laboratory +*- + + IMPLICIT NONE + + REAL R2000,D2000 + + REAL VA(3), VB(3) + + REAL sla_VDV + +* +* Peculiar solar motion from Delhaye 1965: in Galactic Cartesian +* coordinates (+9,+12,+7) km/s. This corresponds to about 16.6 km/s +* towards Galactic coordinates L2 = 53 deg, B2 = +25 deg, or RA,Dec +* 17 49 58.7 +28 07 04 J2000. +* +* 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 / +0.63823, +14.58542, -7.80116 / + + + +* Convert given J2000 RA,Dec to x,y,z + CALL sla_CS2C(R2000,D2000,VB) + +* Compute dot product with solar motion vector + sla_RVLSRD=sla_VDV(VA,VB) + + END -- cgit