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| author | Joseph Hunkeler <jhunkeler@gmail.com> | 2015-03-04 21:21:30 -0500 |
|---|---|---|
| committer | Joseph Hunkeler <jhunkeler@gmail.com> | 2015-03-04 21:21:30 -0500 |
| commit | d54fe7c1f704a63824c5bfa0ece65245572e9b27 (patch) | |
| tree | afc52015ffc2c74e0266653eecef1c8ef8ba5d91 /src/slalib/sun67.htx/node105.html | |
| download | calfuse-d54fe7c1f704a63824c5bfa0ece65245572e9b27.tar.gz | |
Initial commit
Diffstat (limited to 'src/slalib/sun67.htx/node105.html')
| -rw-r--r-- | src/slalib/sun67.htx/node105.html | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/src/slalib/sun67.htx/node105.html b/src/slalib/sun67.htx/node105.html new file mode 100644 index 0000000..dde5fc9 --- /dev/null +++ b/src/slalib/sun67.htx/node105.html @@ -0,0 +1,166 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> +<!--Converted with LaTeX2HTML 97.1 (release) (July 13th, 1997) + by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds +* revised and updated by: Marcus Hennecke, Ross Moore, Herb Swan +* with significant contributions from: + Jens Lippman, Marek Rouchal, Martin Wilck and others --> +<HTML> +<HEAD> +<TITLE>SLA_FK45Z - FK4 to FK5, no P.M. or Parallax</TITLE> +<META NAME="description" CONTENT="SLA_FK45Z - FK4 to FK5, no P.M. or Parallax"> +<META NAME="keywords" CONTENT="sun67"> +<META NAME="resource-type" CONTENT="document"> +<META NAME="distribution" CONTENT="global"> +<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso_8859_1"> +<LINK REL="STYLESHEET" HREF="sun67.css"> +<LINK REL="next" HREF="node106.html"> +<LINK REL="previous" HREF="node104.html"> +<LINK REL="up" HREF="node13.html"> +<LINK REL="next" HREF="node106.html"> +</HEAD> +<BODY > +<BR> <HR> +<A NAME="tex2html1476" HREF="node106.html"> +<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next_motif.gif"></A> +<A NAME="tex2html1474" HREF="node13.html"> +<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up_motif.gif"></A> +<A NAME="tex2html1468" HREF="node104.html"> +<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="previous_motif.gif"></A> <A HREF="sun67.html#stardoccontents"><IMG ALIGN="BOTTOM" BORDER="0" + SRC="contents_motif.gif"></A> +<BR> +<B> Next:</B> <A NAME="tex2html1477" HREF="node106.html">SLA_FK524 - FK5 to FK4</A> +<BR> +<B>Up:</B> <A NAME="tex2html1475" HREF="node13.html">SUBPROGRAM SPECIFICATIONS</A> +<BR> +<B> Previous:</B> <A NAME="tex2html1469" HREF="node104.html">SLA_FK425 - FK4 to FK5</A> +<BR> <HR> <P> +<P><!--End of Navigation Panel--> +<H2><A NAME="SECTION000492000000000000000">SLA_FK45Z - FK4 to FK5, no P.M. or Parallax</A> +<A NAME="xref_SLA_FK45Z"> </A><A NAME="SLA_FK45Z"> </A> +</H2> + <DL> +<DT><STRONG>ACTION:</STRONG> +<DD>Convert B1950.0 FK4 star data to J2000.0 FK5 assuming zero +proper motion in the FK5 frame. + This routine converts stars from the old, Bessel-Newcomb, FK4 + system to the new, IAU 1976, FK5, Fricke system, in such a + way that the FK5 proper motion is zero. Because such a star + has, in general, a non-zero proper motion in the FK4 system, + the routine requires the epoch at which the position in the + FK4 system was determined. The method is from appendix 2 of + reference 1, but using the constants of reference 4. +<P> <DT><STRONG>CALL:</STRONG> +<DD><TT>CALL sla_FK45Z (R1950,D1950,BEPOCH,R2000,D2000)</TT> +<P> </DL> +<P> <DL> +<DT><STRONG>GIVEN:</STRONG> +<DD> +<BR> +<TABLE CELLPADDING=3> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>R1950</EM></TD> +<TH ALIGN="LEFT"><B>D</B></TH> +<TD ALIGN="LEFT" NOWRAP>B1950.0 FK4 <IMG WIDTH="13" HEIGHT="14" ALIGN="BOTTOM" BORDER="0" + SRC="img24.gif" + ALT="$\alpha$"> at epoch BEPOCH (radians)</TD> +</TR> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>D1950</EM></TD> +<TD ALIGN="LEFT"><B>D</B></TD> +<TD ALIGN="LEFT" NOWRAP>B1950.0 FK4 <IMG WIDTH="10" HEIGHT="13" ALIGN="BOTTOM" BORDER="0" + SRC="img23.gif" + ALT="$\delta$"> at epoch BEPOCH (radians)</TD> +</TR> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>BEPOCH</EM></TD> +<TD ALIGN="LEFT"><B>D</B></TD> +<TD ALIGN="LEFT" NOWRAP>Besselian epoch (<I>e.g.</I> 1979.3D0)</TD> +</TR> +</TABLE></DL> +<P> <DL> +<DT><STRONG>RETURNED:</STRONG> +<DD> +<BR> +<TABLE CELLPADDING=3> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>R2000</EM></TD> +<TH ALIGN="LEFT"><B>D</B></TH> +<TD ALIGN="LEFT" NOWRAP>J2000.0 FK5 <IMG WIDTH="13" HEIGHT="14" ALIGN="BOTTOM" BORDER="0" + SRC="img24.gif" + ALT="$\alpha$"> (radians)</TD> +</TR> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>D2000</EM></TD> +<TD ALIGN="LEFT"><B>D</B></TD> +<TD ALIGN="LEFT" NOWRAP>J2000.0 FK5 <IMG WIDTH="10" HEIGHT="13" ALIGN="BOTTOM" BORDER="0" + SRC="img23.gif" + ALT="$\delta$"> (radians)</TD> +</TR> +</TABLE></DL> +<P> <DL> +<DT><STRONG>NOTES:</STRONG> +<DD><DL COMPACT> +<DT>1. +<DD>The epoch BEPOCH is strictly speaking Besselian, but +if a Julian epoch is supplied the result will be +affected only to a negligible extent. + <DT>2. +<DD>Conversion from Besselian epoch 1950.0 to Julian epoch + 2000.0 only is provided for. Conversions involving other + epochs will require use of the appropriate precession, + proper motion, and E-terms routines before and/or + after FK45Z is called. + <DT>3. +<DD>In the FK4 catalogue the proper motions of stars within + <IMG WIDTH="26" HEIGHT="14" ALIGN="BOTTOM" BORDER="0" + SRC="img117.gif" + ALT="$10^{\circ}$"> of the poles do not include the <I>differential + E-terms</I> effect and should, strictly speaking, be handled + in a different manner from stars outside these regions. + However, given the general lack of homogeneity of the star + data available for routine astrometry, the difficulties of + handling positions that may have been determined from + astrometric fields spanning the polar and non-polar regions, + the likelihood that the differential E-terms effect was not + taken into account when allowing for proper motion in past + astrometry, and the undesirability of a discontinuity in + the algorithm, the decision has been made in this routine to + include the effect of differential E-terms on the proper + motions for all stars, whether polar or not. At epoch 2000, + and measuring on the sky rather than in terms of <IMG WIDTH="27" HEIGHT="13" ALIGN="BOTTOM" BORDER="0" + SRC="img118.gif" + ALT="$\Delta\alpha$">, the errors resulting from this simplification are less than + 1 milliarcsecond in position and 1 milliarcsecond per + century in proper motion. + <DT>4. +<DD>See also sla_FK425, sla_FK524, sla_FK54Z. + </DL></DL> +<P> <DL> +<DT><STRONG>REFERENCES:</STRONG> +<DD><DL COMPACT> +<DT>1. +<DD>Aoki, S., <I>et al.</I>, 1983. <I>Astr.Astrophys.</I>, <B>128</B>, 263. +<DT>2. +<DD>Smith, C.A. <I>et al.</I>, 1989. <I>Astr.J.</I> <B>97</B>, 265. +<DT>3. +<DD>Yallop, B.D. <I>et al.</I>, 1989. <I>Astr.J.</I> <B>97</B>, 274. + <DT>4. +<DD>Seidelmann, P.K. (ed), 1992. <I>Explanatory + Supplement to the Astronomical Almanac,</I> ISBN 0-935702-68-7. + </DL></DL> +<BR> <HR> +<A NAME="tex2html1476" HREF="node106.html"> +<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next_motif.gif"></A> +<A NAME="tex2html1474" HREF="node13.html"> +<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up_motif.gif"></A> +<A NAME="tex2html1468" HREF="node104.html"> +<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="previous_motif.gif"></A> <A HREF="sun67.html#stardoccontents"><IMG ALIGN="BOTTOM" BORDER="0" + SRC="contents_motif.gif"></A> +<BR> +<B> Next:</B> <A NAME="tex2html1477" HREF="node106.html">SLA_FK524 - FK5 to FK4</A> +<BR> +<B>Up:</B> <A NAME="tex2html1475" HREF="node13.html">SUBPROGRAM SPECIFICATIONS</A> +<BR> +<B> Previous:</B> <A NAME="tex2html1469" HREF="node104.html">SLA_FK425 - FK4 to FK5</A> +<BR> <HR> <P> +<P><!--End of Navigation Panel--> +<ADDRESS> +<I>SLALIB --- Positional Astronomy Library<BR>Starlink User Note 67<BR>P. T. Wallace<BR>12 October 1999<BR>E-mail:ptw@star.rl.ac.uk</I> +</ADDRESS> +</BODY> +</HTML> |