| 1 | /*
|
|---|
| 2 | *+
|
|---|
| 3 | * Name:
|
|---|
| 4 | * palRvlg
|
|---|
| 5 |
|
|---|
| 6 | * Purpose:
|
|---|
| 7 | * Velocity component in a given direction due to Galactic rotation
|
|---|
| 8 | * and motion of the local group.
|
|---|
| 9 |
|
|---|
| 10 | * Language:
|
|---|
| 11 | * Starlink ANSI C
|
|---|
| 12 |
|
|---|
| 13 | * Type of Module:
|
|---|
| 14 | * Library routine
|
|---|
| 15 |
|
|---|
| 16 | * Invocation:
|
|---|
| 17 | * double palRvlg( double r2000, double d2000 )
|
|---|
| 18 |
|
|---|
| 19 | * Arguments:
|
|---|
| 20 | * r2000 = double (Given)
|
|---|
| 21 | * J2000.0 mean RA (radians)
|
|---|
| 22 | * d2000 = double (Given)
|
|---|
| 23 | * J2000.0 mean Dec (radians)
|
|---|
| 24 |
|
|---|
| 25 | * Returned Value:
|
|---|
| 26 | * Component of SOLAR motion in direction R2000,D2000 (km/s).
|
|---|
| 27 |
|
|---|
| 28 | * Description:
|
|---|
| 29 | * This function returns the velocity component in a given
|
|---|
| 30 | * direction due to the combination of the rotation of the
|
|---|
| 31 | * Galaxy and the motion of the Galaxy relative to the mean
|
|---|
| 32 | * motion of the local group. The result is +ve when the Sun
|
|---|
| 33 | * is receding from the given point on the sky.
|
|---|
| 34 | *
|
|---|
| 35 | * Reference:
|
|---|
| 36 | * - IAU Trans 1976, 168, p201.
|
|---|
| 37 |
|
|---|
| 38 | * Authors:
|
|---|
| 39 | * PTW: Pat Wallace (STFC)
|
|---|
| 40 | * DSB: David Berry (JAC, Hawaii)
|
|---|
| 41 | * {enter_new_authors_here}
|
|---|
| 42 |
|
|---|
| 43 | * History:
|
|---|
| 44 | * 2012-02-16 (DSB):
|
|---|
| 45 | * Initial version.
|
|---|
| 46 | * Adapted with permission from the Fortran SLALIB library.
|
|---|
| 47 | * {enter_further_changes_here}
|
|---|
| 48 |
|
|---|
| 49 | * Copyright:
|
|---|
| 50 | * Copyright (C) 1995 Rutherford Appleton Laboratory
|
|---|
| 51 | * Copyright (C) 2012 Science and Technology Facilities Council.
|
|---|
| 52 | * All Rights Reserved.
|
|---|
| 53 |
|
|---|
| 54 | * Licence:
|
|---|
| 55 | * This program is free software: you can redistribute it and/or
|
|---|
| 56 | * modify it under the terms of the GNU Lesser General Public
|
|---|
| 57 | * License as published by the Free Software Foundation, either
|
|---|
| 58 | * version 3 of the License, or (at your option) any later
|
|---|
| 59 | * version.
|
|---|
| 60 | *
|
|---|
| 61 | * This program is distributed in the hope that it will be useful,
|
|---|
| 62 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|---|
| 63 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|---|
| 64 | * GNU Lesser General Public License for more details.
|
|---|
| 65 | *
|
|---|
| 66 | * You should have received a copy of the GNU Lesser General
|
|---|
| 67 | * License along with this program. If not, see
|
|---|
| 68 | * <http://www.gnu.org/licenses/>.
|
|---|
| 69 |
|
|---|
| 70 | * Bugs:
|
|---|
| 71 | * {note_any_bugs_here}
|
|---|
| 72 | *-
|
|---|
| 73 | */
|
|---|
| 74 |
|
|---|
| 75 | #include "pal.h"
|
|---|
| 76 | #include "pal1sofa.h"
|
|---|
| 77 |
|
|---|
| 78 | double palRvlg( double r2000, double d2000 ){
|
|---|
| 79 |
|
|---|
| 80 | /* Local Variables: */
|
|---|
| 81 | double vb[ 3 ];
|
|---|
| 82 |
|
|---|
| 83 | /*
|
|---|
| 84 | *
|
|---|
| 85 | * Solar velocity due to Galactic rotation and translation
|
|---|
| 86 | *
|
|---|
| 87 | * Speed = 300 km/s
|
|---|
| 88 | *
|
|---|
| 89 | * Apex = L2,B2 90deg, 0deg
|
|---|
| 90 | * = RA,Dec 21 12 01.1 +48 19 47 J2000.0
|
|---|
| 91 | *
|
|---|
| 92 | * This is expressed in the form of a J2000.0 x,y,z vector:
|
|---|
| 93 | *
|
|---|
| 94 | * VA(1) = X = -SPEED*COS(RA)*COS(DEC)
|
|---|
| 95 | * VA(2) = Y = -SPEED*SIN(RA)*COS(DEC)
|
|---|
| 96 | * VA(3) = Z = -SPEED*SIN(DEC)
|
|---|
| 97 | */
|
|---|
| 98 |
|
|---|
| 99 | double va[ 3 ] = { -148.23284, +133.44888, -224.09467 };
|
|---|
| 100 |
|
|---|
| 101 | /* Convert given J2000 RA,Dec to x,y,z. */
|
|---|
| 102 | eraS2c( r2000, d2000, vb );
|
|---|
| 103 |
|
|---|
| 104 | /* Compute dot product with Solar motion vector. */
|
|---|
| 105 | return eraPdp( va, vb );
|
|---|
| 106 | }
|
|---|
