| 1 | #include "slalib.h"
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| 2 | #include "slamac.h"
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| 3 | void slaMap ( double rm, double dm, double pr, double pd,
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| 4 | double px, double rv, double eq, double date,
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| 5 | double *ra, double *da )
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| 6 | /*
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| 7 | ** - - - - - - -
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| 8 | ** s l a M a p
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| 9 | ** - - - - - - -
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| 10 | **
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| 11 | ** Transform star RA,Dec from mean place to geocentric apparent.
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| 12 | **
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| 13 | ** The reference frames and timescales used are post IAU 1976.
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| 14 | **
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| 15 | ** References:
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| 16 | ** 1984 Astronomical Almanac, pp B39-B41.
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| 17 | ** (also Lederle & Schwan, Astron. Astrophys. 134, 1-6, 1984)
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| 18 | **
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| 19 | ** Given:
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| 20 | ** rm,dm double mean RA,Dec (rad)
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| 21 | ** pr,pd double proper motions: RA,Dec changes per Julian year
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| 22 | ** px double parallax (arcsec)
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| 23 | ** rv double radial velocity (km/sec, +ve if receding)
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| 24 | ** eq double epoch and equinox of star data (Julian)
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| 25 | ** date double TDB for apparent place (JD-2400000.5)
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| 26 | **
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| 27 | ** Returned:
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| 28 | ** *ra,*da double apparent RA,Dec (rad)
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| 29 | **
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| 30 | ** Called:
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| 31 | ** slaMappa star-independent parameters
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| 32 | ** slaMapqk quick mean to apparent
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| 33 | **
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| 34 | ** Notes:
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| 35 | **
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| 36 | ** 1) eq is the Julian epoch specifying both the reference
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| 37 | ** frame and the epoch of the position - usually 2000.
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| 38 | ** For positions where the epoch and equinox are
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| 39 | ** different, use the routine slaPm to apply proper
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| 40 | ** motion corrections before using this routine.
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| 41 | **
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| 42 | ** 2) The distinction between the required TDB and TDT is
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| 43 | ** always negligible. Moreover, for all but the most
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| 44 | ** critical applications UTC is adequate.
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| 45 | **
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| 46 | ** 3) The proper motions in RA are dRA/dt rather than
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| 47 | ** cos(dec)*dra/dt.
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| 48 | **
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| 49 | ** 4) This routine may be wasteful for some applications
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| 50 | ** because it recomputes the Earth position/velocity and
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| 51 | ** the precession/nutation matrix each time, and because
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| 52 | ** it allows for parallax and proper motion. Where
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| 53 | ** multiple transformations are to be carried out for one
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| 54 | ** epoch, a faster method is to call the slaMappa routine
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| 55 | ** once and then either the slaMapqk routine (which includes
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| 56 | ** parallax and proper motion) or slaMapqkz (which assumes
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| 57 | ** zero parallax and proper motion).
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| 58 | **
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| 59 | ** Last revision: 12 June 1996
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| 60 | **
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| 61 | ** Copyright P.T.Wallace. All rights reserved.
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| 62 | */
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| 63 | {
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| 64 | double amprms[21];
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| 65 |
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| 66 | /* Star-independent parameters */
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| 67 | slaMappa ( eq, date, amprms );
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| 68 |
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| 69 | /* Mean to apparent */
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| 70 | slaMapqk ( rm, dm, pr, pd, px, rv, amprms, ra, da );
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| 71 | }
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