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| author | Joseph Hunkeler <jhunkeler@gmail.com> | 2015-07-08 20:46:52 -0400 |
|---|---|---|
| committer | Joseph Hunkeler <jhunkeler@gmail.com> | 2015-07-08 20:46:52 -0400 |
| commit | fa080de7afc95aa1c19a6e6fc0e0708ced2eadc4 (patch) | |
| tree | bdda434976bc09c864f2e4fa6f16ba1952b1e555 /math/slalib/doc/fk54z.hlp | |
| download | iraf-linux-fa080de7afc95aa1c19a6e6fc0e0708ced2eadc4.tar.gz | |
Initial commit
Diffstat (limited to 'math/slalib/doc/fk54z.hlp')
| -rw-r--r-- | math/slalib/doc/fk54z.hlp | 56 |
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diff --git a/math/slalib/doc/fk54z.hlp b/math/slalib/doc/fk54z.hlp new file mode 100644 index 00000000..b453bad9 --- /dev/null +++ b/math/slalib/doc/fk54z.hlp @@ -0,0 +1,56 @@ +.help fk54z Jun99 "Slalib Package" +.nf + + SUBROUTINE slF54Z (R2000,D2000,BEPOCH, + : R1950,D1950,DR1950,DD1950) + + - - - - - - + F 5 4 Z + - - - - - - + + Convert a J2000.0 FK5 star position to B1950.0 FK4 assuming + zero proper motion and parallax (double precision) + + This routine converts star positions from the new, IAU 1976, + FK5, Fricke system to the old, Bessel-Newcomb, FK4 system. + + Given: + R2000,D2000 dp J2000.0 FK5 RA,Dec (rad) + BEPOCH dp Besselian epoch (e.g. 1950D0) + + Returned: + R1950,D1950 dp B1950.0 FK4 RA,Dec (rad) at epoch BEPOCH + DR1950,DD1950 dp B1950.0 FK4 proper motions (rad/trop.yr) + + Notes: + + 1) The proper motion in RA is dRA/dt rather than cos(Dec)*dRA/dt. + + 2) Conversion from Julian epoch 2000.0 to Besselian epoch 1950.0 + only is provided for. Conversions involving other epochs will + require use of the appropriate precession routines before and + after this routine is called. + + 3) Unlike in the slFK54 routine, the FK5 proper motions, the + parallax and the radial velocity are presumed zero. + + 4) It is the intention that FK5 should be a close approximation + to an inertial frame, so that distant objects have zero proper + motion; such objects have (in general) non-zero proper motion + in FK4, and this routine returns those fictitious proper + motions. + + 5) The position returned by this routine is in the B1950 + reference frame but at Besselian epoch BEPOCH. For + comparison with catalogues the BEPOCH argument will + frequently be 1950D0. + + Called: slFK54, slPM + + P.T.Wallace Starlink 10 April 1990 + + Copyright (C) 1995 Rutherford Appleton Laboratory + Copyright (C) 1995 Association of Universities for Research in Astronomy Inc. + +.fi +.endhelp |