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Diffstat (limited to 'math/slalib/pm.f')
| -rw-r--r-- | math/slalib/pm.f | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/math/slalib/pm.f b/math/slalib/pm.f new file mode 100644 index 00000000..903f92a8 --- /dev/null +++ b/math/slalib/pm.f @@ -0,0 +1,98 @@ + SUBROUTINE slPM (R0, D0, PR, PD, PX, RV, EP0, EP1, R1, D1) +*+ +* - - - +* P M +* - - - +* +* Apply corrections for proper motion to a star RA,Dec +* (double precision) +* +* References: +* 1984 Astronomical Almanac, pp B39-B41. +* (also Lederle & Schwan, Astron. Astrophys. 134, +* 1-6, 1984) +* +* Given: +* R0,D0 dp RA,Dec at epoch EP0 (rad) +* PR,PD dp proper motions: RA,Dec changes per year of epoch +* PX dp parallax (arcsec) +* RV dp radial velocity (km/sec, +ve if receding) +* EP0 dp start epoch in years (e.g. Julian epoch) +* EP1 dp end epoch in years (same system as EP0) +* +* Returned: +* R1,D1 dp RA,Dec at epoch EP1 (rad) +* +* Called: +* slDS2C spherical to Cartesian +* slDC2S Cartesian to spherical +* slDA2P normalize angle 0-2Pi +* +* Notes: +* +* 1 The proper motions in RA are dRA/dt rather than cos(Dec)*dRA/dt, +* and are in the same coordinate system as R0,D0. +* +* 2 If the available proper motions are pre-FK5 they will be per +* tropical year rather than per Julian year, and so the epochs +* must both be Besselian rather than Julian. In such cases, a +* scaling factor of 365.2422D0/365.25D0 should be applied to the +* radial velocity before use. +* +* P.T.Wallace Starlink 19 January 2000 +* +* Copyright (C) 2000 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., 51 Franklin Street, Fifth Floor, +* Boston, MA 02110-1301 USA +* +* Copyright (C) 1995 Association of Universities for Research in Astronomy Inc. +*- + + IMPLICIT NONE + + DOUBLE PRECISION R0,D0,PR,PD,PX,RV,EP0,EP1,R1,D1 + +* Km/s to AU/year multiplied by arcseconds to radians + DOUBLE PRECISION VFR + PARAMETER (VFR=(365.25D0*86400D0/149597870D0)*4.8481368111D-6) + + INTEGER I + DOUBLE PRECISION slDA2P + DOUBLE PRECISION W,EM(3),T,P(3) + + + +* Spherical to Cartesian + CALL slDS2C(R0,D0,P) + +* Space motion (radians per year) + W=VFR*RV*PX + EM(1)=-PR*P(2)-PD*COS(R0)*SIN(D0)+W*P(1) + EM(2)= PR*P(1)-PD*SIN(R0)*SIN(D0)+W*P(2) + EM(3)= PD*COS(D0) +W*P(3) + +* Apply the motion + T=EP1-EP0 + DO I=1,3 + P(I)=P(I)+T*EM(I) + END DO + +* Cartesian to spherical + CALL slDC2S(P,R1,D1) + R1=slDA2P(R1) + + END |