SUBROUTINE sla_MAP (RM, DM, PR, PD, PX, RV, EQ, DATE, RA, DA) *+ * - - - - * M A P * - - - - * * Transform star RA,Dec from mean place to geocentric apparent * * The reference frames and timescales used are post IAU 1976. * * References: * 1984 Astronomical Almanac, pp B39-B41. * (also Lederle & Schwan, Astron. Astrophys. 134, * 1-6, 1984) * * Given: * RM,DM dp mean RA,Dec (rad) * PR,PD dp proper motions: RA,Dec changes per Julian year * PX dp parallax (arcsec) * RV dp radial velocity (km/sec, +ve if receding) * EQ dp epoch and equinox of star data (Julian) * DATE dp TDB for apparent place (JD-2400000.5) * * Returned: * RA,DA dp apparent RA,Dec (rad) * * Called: * sla_MAPPA star-independent parameters * sla_MAPQK quick mean to apparent * * Notes: * * 1) EQ is the Julian epoch specifying both the reference * frame and the epoch of the position - usually 2000. * For positions where the epoch and equinox are * different, use the routine sla_PM to apply proper * motion corrections before using this routine. * * 2) The distinction between the required TDB and TT is * always negligible. Moreover, for all but the most * critical applications UTC is adequate. * * 3) The proper motions in RA are dRA/dt rather than * cos(Dec)*dRA/dt. * * 4) This routine may be wasteful for some applications * because it recomputes the Earth position/velocity and * the precession/nutation matrix each time, and because * it allows for parallax and proper motion. Where * multiple transformations are to be carried out for one * epoch, a faster method is to call the sla_MAPPA routine * once and then either the sla_MAPQK routine (which includes * parallax and proper motion) or sla_MAPQKZ (which assumes * zero parallax and proper motion). * * P.T.Wallace Starlink 19 January 1993 * * Copyright (C) 1995 Rutherford Appleton Laboratory *- IMPLICIT NONE DOUBLE PRECISION RM,DM,PR,PD,PX,RV,EQ,DATE,RA,DA DOUBLE PRECISION AMPRMS(21) * Star-independent parameters CALL sla_MAPPA(EQ,DATE,AMPRMS) * Mean to apparent CALL sla_MAPQK(RM,DM,PR,PD,PX,RV,AMPRMS,RA,DA) END