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diff --git a/src/slalib/sun67.htx/node77.html b/src/slalib/sun67.htx/node77.html new file mode 100644 index 0000000..522e009 --- /dev/null +++ b/src/slalib/sun67.htx/node77.html @@ -0,0 +1,117 @@ +<!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_DTP2V - Tangent Plane to Direction Cosines</TITLE> +<META NAME="description" CONTENT="SLA_DTP2V - Tangent Plane to Direction Cosines"> +<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="node78.html"> +<LINK REL="previous" HREF="node76.html"> +<LINK REL="up" HREF="node13.html"> +<LINK REL="next" HREF="node78.html"> +</HEAD> +<BODY > +<BR> <HR> +<A NAME="tex2html1196" HREF="node78.html"> +<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next_motif.gif"></A> +<A NAME="tex2html1194" HREF="node13.html"> +<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up_motif.gif"></A> +<A NAME="tex2html1188" HREF="node76.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="tex2html1197" HREF="node78.html">SLA_DTPS2C - Plate centre from and</A> +<BR> +<B>Up:</B> <A NAME="tex2html1195" HREF="node13.html">SUBPROGRAM SPECIFICATIONS</A> +<BR> +<B> Previous:</B> <A NAME="tex2html1189" HREF="node76.html">SLA_DTP2S - Tangent Plane to Spherical</A> +<BR> <HR> <P> +<P><!--End of Navigation Panel--> +<H2><A NAME="SECTION000464000000000000000">SLA_DTP2V - Tangent Plane to Direction Cosines</A> +<A NAME="xref_SLA_DTP2V"> </A><A NAME="SLA_DTP2V"> </A> +</H2> + <DL> +<DT><STRONG>ACTION:</STRONG> +<DD>Given the tangent-plane coordinates of a star and the direction +cosines of the tangent point, determine the direction cosines + of the star + (double precision). +<P> <DT><STRONG>CALL:</STRONG> +<DD><TT>CALL sla_DTP2V (XI, ETA, V0, V)</TT> +<P> </DL> +<P> <DL> +<DT><STRONG>GIVEN:</STRONG> +<DD> +<BR> +<TABLE CELLPADDING=3> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>XI,ETA</EM></TD> +<TH ALIGN="LEFT"><B>D</B></TH> +<TD ALIGN="LEFT" NOWRAP>tangent plane coordinates of star (radians)</TD> +</TR> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>V0</EM></TD> +<TD ALIGN="LEFT"><B>D(3)</B></TD> +<TD ALIGN="LEFT" NOWRAP>direction cosines of tangent point</TD> +</TR> +</TABLE></DL> +<P> <DL> +<DT><STRONG>RETURNED:</STRONG> +<DD> +<BR> +<TABLE CELLPADDING=3> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>V</EM></TD> +<TH ALIGN="LEFT"><B>D(3)</B></TH> +<TD ALIGN="LEFT" NOWRAP>direction cosines of star</TD> +</TR> +</TABLE></DL> +<P> <DL> +<DT><STRONG>NOTES:</STRONG> +<DD><DL COMPACT> +<DT>1. +<DD>If vector V0 is not of unit length, the returned vector V will +be wrong. +<DT>2. +<DD>If vector V0 points at a pole, the returned vector V will be + based on the arbitrary assumption that <IMG WIDTH="43" HEIGHT="14" ALIGN="BOTTOM" BORDER="0" + SRC="img89.gif" + ALT="$\alpha=0$"> at + the tangent point. + <DT>3. +<DD>The projection is called the <I>gnomonic</I> projection; the + Cartesian coordinates <IMG WIDTH="41" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" + SRC="img85.gif" + ALT="$[\,\xi,\eta\,]$"> are called + <I>standard coordinates.</I> The latter + are in units of the distance from the tangent plane to the projection + point, <I>i.e.</I> radians near the origin. + <DT>4. +<DD>This routine is the Cartesian equivalent of the routine sla_DTP2S. + </DL></DL> +<BR> <HR> +<A NAME="tex2html1196" HREF="node78.html"> +<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next_motif.gif"></A> +<A NAME="tex2html1194" HREF="node13.html"> +<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up_motif.gif"></A> +<A NAME="tex2html1188" HREF="node76.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="tex2html1197" HREF="node78.html">SLA_DTPS2C - Plate centre from and</A> +<BR> +<B>Up:</B> <A NAME="tex2html1195" HREF="node13.html">SUBPROGRAM SPECIFICATIONS</A> +<BR> +<B> Previous:</B> <A NAME="tex2html1189" HREF="node76.html">SLA_DTP2S - Tangent Plane to Spherical</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> |