mirror of
https://github.com/eddyem/apogee_control.git
synced 2025-12-06 10:45:20 +03:00
87 lines
2.5 KiB
Fortran
87 lines
2.5 KiB
Fortran
REAL FUNCTION sla_RVGALC (R2000, D2000)
|
|
*+
|
|
* - - - - - - -
|
|
* R V G A L C
|
|
* - - - - - - -
|
|
*
|
|
* Velocity component in a given direction due to the rotation
|
|
* of the Galaxy (single precision)
|
|
*
|
|
* Given:
|
|
* R2000,D2000 real J2000.0 mean RA,Dec (radians)
|
|
*
|
|
* Result:
|
|
* Component of dynamical LSR motion in direction R2000,D2000 (km/s)
|
|
*
|
|
* Sign convention:
|
|
* The result is +ve when the dynamical LSR is receding from the
|
|
* given point on the sky.
|
|
*
|
|
* Note: The Local Standard of Rest used here is a point in the
|
|
* vicinity of the Sun which is in a circular orbit around
|
|
* the Galactic centre. Sometimes called the "dynamical" LSR,
|
|
* it is not to be confused with a "kinematical" LSR, which
|
|
* is the mean standard of rest of star catalogues or stellar
|
|
* populations.
|
|
*
|
|
* Reference: The orbital speed of 220 km/s used here comes from
|
|
* Kerr & Lynden-Bell (1986), MNRAS, 221, p1023.
|
|
*
|
|
* Called:
|
|
* sla_CS2C, sla_VDV
|
|
*
|
|
* P.T.Wallace Starlink 23 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
|
|
|
|
*
|
|
* LSR velocity due to Galactic rotation
|
|
*
|
|
* Speed = 220 km/s
|
|
* Apex = L2,B2 90deg, 0deg
|
|
* = RA,Dec 21 12 01.1 +48 19 47 J2000.0
|
|
*
|
|
* This is expressed in the form of a J2000.0 x,y,z 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 / -108.70408, +97.86251, -164.33610 /
|
|
|
|
|
|
|
|
* Convert given J2000 RA,Dec to x,y,z
|
|
CALL sla_CS2C(R2000,D2000,VB)
|
|
|
|
* Compute dot product with LSR motion vector
|
|
sla_RVGALC=sla_VDV(VA,VB)
|
|
|
|
END
|