#include "slalib.h" #include "slamac.h" void slaMap ( double rm, double dm, double pr, double pd, double px, double rv, double eq, double date, double *ra, double *da ) /* ** - - - - - - - ** s l a 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 double mean RA,Dec (rad) ** pr,pd double proper motions: RA,Dec changes per Julian year ** px double parallax (arcsec) ** rv double radial velocity (km/sec, +ve if receding) ** eq double epoch and equinox of star data (Julian) ** date double TDB for apparent place (JD-2400000.5) ** ** Returned: ** *ra,*da double apparent RA,Dec (rad) ** ** Called: ** slaMappa star-independent parameters ** slaMapqk 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 slaPm to apply proper ** motion corrections before using this routine. ** ** 2) The distinction between the required TDB and TDT 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 slaMappa routine ** once and then either the slaMapqk routine (which includes ** parallax and proper motion) or slaMapqkz (which assumes ** zero parallax and proper motion). ** ** Last revision: 12 June 1996 ** ** Copyright P.T.Wallace. All rights reserved. */ { double amprms[21]; /* Star-independent parameters */ slaMappa ( eq, date, amprms ); /* Mean to apparent */ slaMapqk ( rm, dm, pr, pd, px, rv, amprms, ra, da ); }