diff options
Diffstat (limited to 'src/slalib/sun67.htx/node196.html')
| -rw-r--r-- | src/slalib/sun67.htx/node196.html | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/src/slalib/sun67.htx/node196.html b/src/slalib/sun67.htx/node196.html new file mode 100644 index 0000000..0dc168b --- /dev/null +++ b/src/slalib/sun67.htx/node196.html @@ -0,0 +1,137 @@ +<!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_ZD - to Zenith Distance</TITLE> +<META NAME="description" CONTENT="SLA_ZD - to Zenith Distance"> +<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="previous" HREF="node195.html"> +<LINK REL="up" HREF="node13.html"> +<LINK REL="next" HREF="node197.html"> +</HEAD> +<BODY > +<BR> <HR> +<A NAME="tex2html2384" HREF="node197.html"> +<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next_motif.gif"></A> +<A NAME="tex2html2382" HREF="node13.html"> +<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up_motif.gif"></A> +<A NAME="tex2html2378" HREF="node195.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="tex2html2385" HREF="node197.html">EXPLANATION AND EXAMPLES</A> +<BR> +<B>Up:</B> <A NAME="tex2html2383" HREF="node13.html">SUBPROGRAM SPECIFICATIONS</A> +<BR> +<B> Previous:</B> <A NAME="tex2html2379" HREF="node195.html">SLA_XY2XY - Apply Linear Model to an</A> +<BR> <HR> <P> +<P><!--End of Navigation Panel--> +<H2><A NAME="SECTION0004183000000000000000"> </A><A NAME="xref_SLA_ZD"> </A><A NAME="SLA_ZD"> </A> +<BR> +SLA_ZD - <IMG WIDTH="27" HEIGHT="27" ALIGN="MIDDLE" BORDER="0" + SRC="img65.gif" + ALT="$h,\delta$"> to Zenith Distance +</H2> + <DL> +<DT><STRONG>ACTION:</STRONG> +<DD>Hour angle and declination to zenith distance +(double precision). +<P> <DT><STRONG>CALL:</STRONG> +<DD><TT>D = sla_ZD (HA, DEC, PHI)</TT> +<P> </DL> +<P> <DL> +<DT><STRONG>GIVEN:</STRONG> +<DD> +<BR> +<TABLE CELLPADDING=3> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>HA</EM></TD> +<TH ALIGN="LEFT"><B>D</B></TH> +<TD ALIGN="LEFT" NOWRAP>hour angle in radians</TD> +</TR> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>DEC</EM></TD> +<TD ALIGN="LEFT"><B>D</B></TD> +<TD ALIGN="LEFT" NOWRAP>declination in radians</TD> +</TR> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>PHI</EM></TD> +<TD ALIGN="LEFT"><B>D</B></TD> +<TD ALIGN="LEFT" NOWRAP>latitude in radians</TD> +</TR> +</TABLE></DL> +<P> <DL> +<DT><STRONG>RETURNED:</STRONG> +<DD> +<BR> +<TABLE CELLPADDING=3> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>sla_ZD</EM></TD> +<TH ALIGN="LEFT"><B>D</B></TH> +<TD ALIGN="LEFT" NOWRAP>zenith distance (radians, <IMG WIDTH="35" HEIGHT="25" ALIGN="MIDDLE" BORDER="0" + SRC="img234.gif" + ALT="$0\!-\!\pi$">)</TD> +</TR> +</TABLE></DL> +<P> <DL> +<DT><STRONG>NOTES:</STRONG> +<DD><DL COMPACT> +<DT>1. +<DD>The latitude must be geodetic. In critical applications, +corrections for polar motion should be applied (see sla_POLMO). +<DT>2. +<DD>In some applications it will be important to specify the + correct type of hour angle and declination in order to + produce the required type + of zenith distance. In particular, it may be + important to distinguish between the zenith distance + as affected by refraction, which would require the + <I>observed</I> <IMG WIDTH="41" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" + SRC="img29.gif" + ALT="$[\,h,\delta\,]$">, and the zenith distance <I>in vacuo</I>, + which would require the <I>topocentric</I> <IMG WIDTH="41" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" + SRC="img29.gif" + ALT="$[\,h,\delta\,]$">. If + the effects of diurnal aberration can be neglected, the + <I>apparent</I> <IMG WIDTH="41" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" + SRC="img29.gif" + ALT="$[\,h,\delta\,]$"> may be used instead of the + <I>topocentric</I> <IMG WIDTH="41" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" + SRC="img29.gif" + ALT="$[\,h,\delta\,]$">. <DT>3. +<DD>No range checking of arguments is done. + <DT>4. +<DD>In applications which involve many zenith distance calculations, + rather than calling the present routine it will be more + efficient to use inline code, having previously computed fixed + terms such as sine and cosine of latitude, and perhaps sine and + cosine of declination. + </DL></DL> +<P> +<BR> +<P> +<BR> <HR> +<A NAME="tex2html2384" HREF="node197.html"> +<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next_motif.gif"></A> +<A NAME="tex2html2382" HREF="node13.html"> +<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up_motif.gif"></A> +<A NAME="tex2html2378" HREF="node195.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="tex2html2385" HREF="node197.html">EXPLANATION AND EXAMPLES</A> +<BR> +<B>Up:</B> <A NAME="tex2html2383" HREF="node13.html">SUBPROGRAM SPECIFICATIONS</A> +<BR> +<B> Previous:</B> <A NAME="tex2html2379" HREF="node195.html">SLA_XY2XY - Apply Linear Model to an</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> |