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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/node46.html | |
| download | calfuse-d54fe7c1f704a63824c5bfa0ece65245572e9b27.tar.gz | |
Initial commit
Diffstat (limited to 'src/slalib/sun67.htx/node46.html')
| -rw-r--r-- | src/slalib/sun67.htx/node46.html | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/src/slalib/sun67.htx/node46.html b/src/slalib/sun67.htx/node46.html new file mode 100644 index 0000000..39a1ffd --- /dev/null +++ b/src/slalib/sun67.htx/node46.html @@ -0,0 +1,123 @@ +<!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_DBEAR - Direction Between Points on a Sphere</TITLE> +<META NAME="description" CONTENT="SLA_DBEAR - Direction Between Points on a Sphere"> +<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="node47.html"> +<LINK REL="previous" HREF="node45.html"> +<LINK REL="up" HREF="node13.html"> +<LINK REL="next" HREF="node47.html"> +</HEAD> +<BODY > +<BR> <HR> +<A NAME="tex2html886" HREF="node47.html"> +<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next_motif.gif"></A> +<A NAME="tex2html884" HREF="node13.html"> +<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up_motif.gif"></A> +<A NAME="tex2html878" HREF="node45.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="tex2html887" HREF="node47.html">SLA_DBJIN - Decode String to B/J Epoch (DP)</A> +<BR> +<B>Up:</B> <A NAME="tex2html885" HREF="node13.html">SUBPROGRAM SPECIFICATIONS</A> +<BR> +<B> Previous:</B> <A NAME="tex2html879" HREF="node45.html">SLA_DAV2M - Rotation Matrix from Axial Vector</A> +<BR> <HR> <P> +<P><!--End of Navigation Panel--> +<H2><A NAME="SECTION000433000000000000000">SLA_DBEAR - Direction Between Points on a Sphere</A> +<A NAME="xref_SLA_DBEAR"> </A><A NAME="SLA_DBEAR"> </A> +</H2> + <DL> +<DT><STRONG>ACTION:</STRONG> +<DD>Returns the bearing (position angle) of one point on a +sphere relative to another (double precision). +<P> <DT><STRONG>CALL:</STRONG> +<DD><TT>D = sla_DBEAR (A1, B1, A2, B2)</TT> +<P> </DL> +<P> <DL> +<DT><STRONG>GIVEN:</STRONG> +<DD> +<BR> +<TABLE CELLPADDING=3> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>A1,B1</EM></TD> +<TH ALIGN="LEFT"><B>D</B></TH> +<TD ALIGN="LEFT" NOWRAP>spherical coordinates of one point</TD> +</TR> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>A2,B2</EM></TD> +<TD ALIGN="LEFT"><B>D</B></TD> +<TD ALIGN="LEFT" NOWRAP>spherical coordinates of the other point</TD> +</TR> +</TABLE></DL> +<P> <DL> +<DT><STRONG>RETURNED:</STRONG> +<DD> +<BR> +<TABLE CELLPADDING=3> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>sla_DBEAR</EM></TD> +<TH ALIGN="LEFT"><B>D</B></TH> +<TD ALIGN="LEFT" NOWRAP>bearing from first point to second</TD> +</TR> +</TABLE></DL> +<P> <DL> +<DT><STRONG>NOTES:</STRONG> +<DD><DL COMPACT> +<DT>1. +<DD>The spherical coordinates are <IMG WIDTH="42" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" + SRC="img3.gif" + ALT="$[\,\alpha,\delta\,]$">,<IMG WIDTH="38" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" + SRC="img46.gif" + ALT="$[\lambda,\phi]$"> <I>etc.</I>, in radians. +<DT>2. +<DD>The result is the bearing (position angle), in radians, + of point [A2,B2] as seen + from point [A1,B1]. It is in the range <IMG WIDTH="25" HEIGHT="25" ALIGN="MIDDLE" BORDER="0" + SRC="img47.gif" + ALT="$\pm \pi$">. The sense + is such that if [A2,B2] + is a small distance due east of [A1,B1] the result + is about <IMG WIDTH="41" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" + SRC="img14.gif" + ALT="$+\pi/2$">. Zero is returned + if the two points are coincident. + <DT>3. +<DD>If either B-coordinate is outside the range <IMG WIDTH="41" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" + SRC="img15.gif" + ALT="$\pm\pi/2$">, the + result may correspond to ``the long way round''. + <DT>4. +<DD>The routine sla_DPAV performs an equivalent function except + that the points are specified in the form of Cartesian unit + vectors. + </DL></DL> +<BR> <HR> +<A NAME="tex2html886" HREF="node47.html"> +<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next_motif.gif"></A> +<A NAME="tex2html884" HREF="node13.html"> +<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up_motif.gif"></A> +<A NAME="tex2html878" HREF="node45.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="tex2html887" HREF="node47.html">SLA_DBJIN - Decode String to B/J Epoch (DP)</A> +<BR> +<B>Up:</B> <A NAME="tex2html885" HREF="node13.html">SUBPROGRAM SPECIFICATIONS</A> +<BR> +<B> Previous:</B> <A NAME="tex2html879" HREF="node45.html">SLA_DAV2M - Rotation Matrix from Axial Vector</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> |