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Diffstat (limited to 'math/slalib/amp.f')
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diff --git a/math/slalib/amp.f b/math/slalib/amp.f new file mode 100644 index 00000000..d6aff8df --- /dev/null +++ b/math/slalib/amp.f @@ -0,0 +1,89 @@ + SUBROUTINE slAMP (RA, DA, DATE, EQ, RM, DM) +*+ +* - - - - +* A M P +* - - - - +* +* Convert star RA,Dec from geocentric apparent to mean place +* +* The mean coordinate system is the post IAU 1976 system, +* loosely called FK5. +* +* Given: +* RA d apparent RA (radians) +* DA d apparent Dec (radians) +* DATE d TDB for apparent place (JD-2400000.5) +* EQ d equinox: Julian epoch of mean place +* +* Returned: +* RM d mean RA (radians) +* DM d mean Dec (radians) +* +* References: +* 1984 Astronomical Almanac, pp B39-B41. +* (also Lederle & Schwan, Astron. Astrophys. 134, +* 1-6, 1984) +* +* Notes: +* +* 1) The distinction between the required TDB and TT is always +* negligible. Moreover, for all but the most critical +* applications UTC is adequate. +* +* 2) Iterative techniques are used for the aberration and light +* deflection corrections so that the routines slAMP (or +* slAMPQ) and slMAP (or slMAPQ) are accurate inverses; +* even at the edge of the Sun's disc the discrepancy is only +* about 1 nanoarcsecond. +* +* 3) Where multiple apparent places are to be converted to mean +* places, for a fixed date and equinox, it is more efficient to +* use the slMAPA routine to compute the required parameters +* once, followed by one call to slAMPQ per star. +* +* 4) The accuracy is sub-milliarcsecond, limited by the +* precession-nutation model (IAU 1976 precession, Shirai & +* Fukushima 2001 forced nutation and precession corrections). +* +* 5) The accuracy is further limited by the routine slEVP, called +* by slMAPA, which computes the Earth position and velocity +* using the methods of Stumpff. The maximum error is about +* 0.3 mas. +* +* Called: slMAPA, slAMPQ +* +* P.T.Wallace Starlink 17 September 2001 +* +* Copyright (C) 2001 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 RA,DA,DATE,EQ,RM,DM + + DOUBLE PRECISION AMPRMS(21) + + + + CALL slMAPA(EQ,DATE,AMPRMS) + CALL slAMPQ(RA,DA,AMPRMS,RM,DM) + + END |