Initial commit

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/node168.html
download: calfuse-d54fe7c1f704a63824c5bfa0ece65245572e9b27.tar.gz
1 files changed, 276 insertions, 0 deletions
diff --git a/src/slalib/sun67.htx/node168.html b/src/slalib/sun67.htx/node168.html
new file mode 100644
index 0000000..c695ed9
--- /dev/null
+++ b/src/slalib/sun67.htx/node168.html
@@ -0,0 +1,276 @@
+<!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_REFV - Apply Refraction to Vector</TITLE>
+<META NAME="description" CONTENT="SLA_REFV - Apply Refraction to Vector">
+<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="node169.html">
+<LINK REL="previous" HREF="node167.html">
+<LINK REL="up" HREF="node13.html">
+<LINK REL="next" HREF="node169.html">
+</HEAD>
+<BODY >
+<BR> <HR>
+<A NAME="tex2html2106" HREF="node169.html">
+<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next_motif.gif"></A> 
+<A NAME="tex2html2104" HREF="node13.html">
+<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up_motif.gif"></A> 
+<A NAME="tex2html2098" HREF="node167.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="tex2html2107" HREF="node169.html">SLA_REFZ - Apply Refraction to ZD</A>
+<BR>
+<B>Up:</B> <A NAME="tex2html2105" HREF="node13.html">SUBPROGRAM SPECIFICATIONS</A>
+<BR>
+<B> Previous:</B> <A NAME="tex2html2099" HREF="node167.html">SLA_REFRO - Refraction</A>
+<BR> <HR> <P>
+<P><!--End of Navigation Panel-->
+<H2><A NAME="SECTION0004155000000000000000">SLA_REFV - Apply Refraction to Vector</A>
+<A NAME="xref_SLA_REFV">&#160;</A><A NAME="SLA_REFV">&#160;</A>
+</H2>
+       <DL>
+<DT><STRONG>ACTION:</STRONG>
+<DD>Adjust an unrefracted Cartesian vector to include the effect of
+atmospheric refraction, using the simple
+         <IMG WIDTH="164" HEIGHT="31" ALIGN="MIDDLE" BORDER="0"
+ SRC="img148.gif"
+ ALT="$\Delta \zeta = a \tan \zeta + b \tan^{3} \zeta$"> model.
+<P>    <DT><STRONG>CALL:</STRONG>
+<DD><TT>CALL sla_REFV (VU, REFA, REFB, VR)</TT>
+<P>       </DL>
+<P>     <DL>
+<DT><STRONG>GIVEN:</STRONG>
+<DD>
+<BR>
+<TABLE CELLPADDING=3>
+<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>VU</EM></TD>
+<TH ALIGN="LEFT"><B>D</B></TH>
+<TD ALIGN="LEFT" NOWRAP>unrefracted position of the source (<IMG WIDTH="66" HEIGHT="29" ALIGN="MIDDLE" BORDER="0"
+ SRC="img28.gif"
+ ALT="$[\,Az,El~]$"> 3-vector)</TD>
+</TR>
+<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>REFA</EM></TD>
+<TD ALIGN="LEFT"><B>D</B></TD>
+<TD ALIGN="LEFT" NOWRAP><IMG WIDTH="37" HEIGHT="27" ALIGN="MIDDLE" BORDER="0"
+ SRC="img151.gif"
+ ALT="$\tan \zeta$"> coefficient (radians)</TD>
+</TR>
+<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>REFB</EM></TD>
+<TD ALIGN="LEFT"><B>D</B></TD>
+<TD ALIGN="LEFT" NOWRAP><IMG WIDTH="44" HEIGHT="31" ALIGN="MIDDLE" BORDER="0"
+ SRC="img152.gif"
+ ALT="$\tan^{3} \zeta$"> coefficient (radians)</TD>
+</TR>
+</TABLE></DL>
+<P>     <DL>
+<DT><STRONG>RETURNED:</STRONG>
+<DD>
+<BR>
+<TABLE CELLPADDING=3>
+<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>VR</EM></TD>
+<TH ALIGN="LEFT"><B>D</B></TH>
+<TD ALIGN="LEFT" NOWRAP>refracted position of the source (<IMG WIDTH="66" HEIGHT="29" ALIGN="MIDDLE" BORDER="0"
+ SRC="img28.gif"
+ ALT="$[\,Az,El~]$"> 3-vector)</TD>
+</TR>
+</TABLE></DL>
+<P>      <DL>
+<DT><STRONG>NOTES:</STRONG>
+<DD><DL COMPACT>
+<DT>1.
+<DD>This routine applies the adjustment for refraction in the
+opposite sense to the usual one - it takes an unrefracted
+(<I>in vacuo</I>) position and produces an observed (refracted)
+        position, whereas the
+        <IMG WIDTH="164" HEIGHT="31" ALIGN="MIDDLE" BORDER="0"
+ SRC="img148.gif"
+ ALT="$\Delta \zeta = a \tan \zeta + b \tan^{3} \zeta$">        model strictly
+        applies to the case where an observed position is to have the
+        refraction removed.  The unrefracted to refracted case is
+        harder, and requires an inverted form of the text-book
+        refraction models;  the algorithm used here is equivalent to
+        one iteration of the Newton-Raphson method applied to the
+        above formula.
+  <DT>2.
+<DD>Though optimized for speed rather than precision, the present
+        routine achieves consistency with the refracted-to-unrefracted
+        <IMG WIDTH="164" HEIGHT="31" ALIGN="MIDDLE" BORDER="0"
+ SRC="img148.gif"
+ ALT="$\Delta \zeta = a \tan \zeta + b \tan^{3} \zeta$">        model at better than 1&nbsp;microarcsecond within
+        <IMG WIDTH="26" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
+ SRC="img182.gif"
+ ALT="$30^\circ$"> of the zenith and remains within 1&nbsp;milliarcsecond to
+        <IMG WIDTH="56" HEIGHT="27" ALIGN="MIDDLE" BORDER="0"
+ SRC="img183.gif"
+ ALT="$\zeta=70^\circ$">.  The inherent accuracy of the model is, of
+        course, far worse than this - see the documentation for sla_REFCO
+        for more information.
+  <DT>3.
+<DD>At low elevations (below about <IMG WIDTH="18" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
+ SRC="img27.gif"
+ ALT="$3^{\circ}$">) the refraction
+        correction is held back to prevent arithmetic problems and
+        wildly wrong results.  Over a wide range of observer heights
+        and corresponding temperatures and pressures, the following
+        levels of accuracy are achieved, relative to numerical
+        integration through a model atmosphere:
+<P>        <DIV ALIGN="CENTER">
+<TABLE CELLPADDING=3>
+<TR VALIGN="TOP"><TD ALIGN="CENTER" NOWRAP><IMG WIDTH="28" HEIGHT="27" ALIGN="MIDDLE" BORDER="0"
+ SRC="img184.gif"
+ ALT="$\zeta_{obs}$"></TD>
+<TH ALIGN="CENTER" NOWRAP><I>error</I></TH>
+<TD ALIGN="LEFT" NOWRAP>&nbsp;</TD>
+</TR>
+<TR VALIGN="TOP"><TD ALIGN="CENTER" NOWRAP>&nbsp;</TD>
+<TD ALIGN="CENTER" NOWRAP>&nbsp;</TD>
+<TD ALIGN="LEFT" NOWRAP>&nbsp;</TD>
+</TR>
+<TR VALIGN="TOP"><TD ALIGN="CENTER" NOWRAP><IMG WIDTH="26" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
+ SRC="img179.gif"
+ ALT="$80^\circ$"></TD>
+<TD ALIGN="CENTER" NOWRAP><IMG WIDTH="23" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
+ SRC="img185.gif"
+ ALT="$0\hspace{-0.05em}^{'\hspace{-0.1em}'}\hspace{-0.4em}.4$"></TD>
+<TD ALIGN="LEFT" NOWRAP>&nbsp;</TD>
+</TR>
+<TR VALIGN="TOP"><TD ALIGN="CENTER" NOWRAP><IMG WIDTH="26" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
+ SRC="img186.gif"
+ ALT="$81^\circ$"></TD>
+<TD ALIGN="CENTER" NOWRAP><IMG WIDTH="23" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
+ SRC="img187.gif"
+ ALT="$0\hspace{-0.05em}^{'\hspace{-0.1em}'}\hspace{-0.4em}.8$"></TD>
+<TD ALIGN="LEFT" NOWRAP>&nbsp;</TD>
+</TR>
+<TR VALIGN="TOP"><TD ALIGN="CENTER" NOWRAP><IMG WIDTH="26" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
+ SRC="img188.gif"
+ ALT="$82^\circ$"></TD>
+<TD ALIGN="CENTER" NOWRAP><IMG WIDTH="23" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
+ SRC="img189.gif"
+ ALT="$1\hspace{-0.05em}^{'\hspace{-0.1em}'}\hspace{-0.4em}.6$"></TD>
+<TD ALIGN="LEFT" NOWRAP>&nbsp;</TD>
+</TR>
+<TR VALIGN="TOP"><TD ALIGN="CENTER" NOWRAP><IMG WIDTH="26" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
+ SRC="img190.gif"
+ ALT="$83^\circ$"></TD>
+<TD ALIGN="CENTER" NOWRAP><IMG WIDTH="17" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
+ SRC="img75.gif"
+ ALT="$3\hspace{-0.05em}^{'\hspace{-0.1em}'}$"></TD>
+<TD ALIGN="LEFT" NOWRAP>&nbsp;</TD>
+</TR>
+<TR VALIGN="TOP"><TD ALIGN="CENTER" NOWRAP><IMG WIDTH="26" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
+ SRC="img191.gif"
+ ALT="$84^\circ$"></TD>
+<TD ALIGN="CENTER" NOWRAP><IMG WIDTH="17" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
+ SRC="img192.gif"
+ ALT="$7\hspace{-0.05em}^{'\hspace{-0.1em}'}$"></TD>
+<TD ALIGN="LEFT" NOWRAP>&nbsp;</TD>
+</TR>
+<TR VALIGN="TOP"><TD ALIGN="CENTER" NOWRAP><IMG WIDTH="26" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
+ SRC="img193.gif"
+ ALT="$85^\circ$"></TD>
+<TD ALIGN="CENTER" NOWRAP><IMG WIDTH="25" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
+ SRC="img133.gif"
+ ALT="$17\hspace{-0.05em}^{'\hspace{-0.1em}'}$"></TD>
+<TD ALIGN="LEFT" NOWRAP>&nbsp;</TD>
+</TR>
+<TR VALIGN="TOP"><TD ALIGN="CENTER" NOWRAP><IMG WIDTH="26" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
+ SRC="img194.gif"
+ ALT="$86^\circ$"></TD>
+<TD ALIGN="CENTER" NOWRAP><IMG WIDTH="25" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
+ SRC="img195.gif"
+ ALT="$45\hspace{-0.05em}^{'\hspace{-0.1em}'}$"></TD>
+<TD ALIGN="LEFT" NOWRAP>&nbsp;</TD>
+</TR>
+<TR VALIGN="TOP"><TD ALIGN="CENTER" NOWRAP><IMG WIDTH="26" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
+ SRC="img196.gif"
+ ALT="$87^\circ$"></TD>
+<TD ALIGN="CENTER" NOWRAP><IMG WIDTH="33" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
+ SRC="img197.gif"
+ ALT="$150\hspace{-0.05em}^{'\hspace{-0.1em}'}$"></TD>
+<TD ALIGN="LEFT" NOWRAP>&nbsp;</TD>
+</TR>
+<TR VALIGN="TOP"><TD ALIGN="CENTER" NOWRAP><IMG WIDTH="26" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
+ SRC="img198.gif"
+ ALT="$88^\circ$"></TD>
+<TD ALIGN="CENTER" NOWRAP><IMG WIDTH="33" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
+ SRC="img199.gif"
+ ALT="$340\hspace{-0.05em}^{'\hspace{-0.1em}'}$"></TD>
+<TD ALIGN="LEFT" NOWRAP>&nbsp;</TD>
+</TR>
+<TR VALIGN="TOP"><TD ALIGN="CENTER" NOWRAP><IMG WIDTH="26" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
+ SRC="img200.gif"
+ ALT="$89^\circ$"></TD>
+<TD ALIGN="CENTER" NOWRAP><IMG WIDTH="33" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
+ SRC="img201.gif"
+ ALT="$620\hspace{-0.05em}^{'\hspace{-0.1em}'}$"></TD>
+<TD ALIGN="LEFT" NOWRAP>&nbsp;</TD>
+</TR>
+<TR VALIGN="TOP"><TD ALIGN="CENTER" NOWRAP><IMG WIDTH="26" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
+ SRC="img22.gif"
+ ALT="$90^{\circ}$"></TD>
+<TD ALIGN="CENTER" NOWRAP><IMG WIDTH="41" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
+ SRC="img202.gif"
+ ALT="$1100\hspace{-0.05em}^{'\hspace{-0.1em}'}$"></TD>
+<TD ALIGN="LEFT" NOWRAP>&nbsp;</TD>
+</TR>
+<TR VALIGN="TOP"><TD ALIGN="CENTER" NOWRAP><IMG WIDTH="26" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
+ SRC="img203.gif"
+ ALT="$91^\circ$"></TD>
+<TD ALIGN="CENTER" NOWRAP><IMG WIDTH="41" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
+ SRC="img204.gif"
+ ALT="$1900\hspace{-0.05em}^{'\hspace{-0.1em}'}$"></TD>
+<TD ALIGN="LEFT" NOWRAP>&lt; high-altitude</TD>
+</TR>
+<TR VALIGN="TOP"><TD ALIGN="CENTER" NOWRAP><IMG WIDTH="26" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
+ SRC="img205.gif"
+ ALT="$92^\circ$"></TD>
+<TD ALIGN="CENTER" NOWRAP><IMG WIDTH="41" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
+ SRC="img206.gif"
+ ALT="$3200\hspace{-0.05em}^{'\hspace{-0.1em}'}$"></TD>
+<TD ALIGN="LEFT" NOWRAP>&lt; sites only</TD>
+</TR>
+</TABLE></DIV>
+  <DT>4.
+<DD>See also the routine sla_REFZ, which performs the adjustment to
+        the zenith distance rather than in <IMG WIDTH="58" HEIGHT="29" ALIGN="MIDDLE" BORDER="0"
+ SRC="img50.gif"
+ ALT="$[\,x,y,z\,]$">.        The present routine is faster than sla_REFZ and,
+        except very low down,
+        is equally accurate for all practical purposes.  However, beyond
+        about <IMG WIDTH="56" HEIGHT="27" ALIGN="MIDDLE" BORDER="0"
+ SRC="img207.gif"
+ ALT="$\zeta=84^\circ$"> sla_REFZ should be used, and for the utmost
+        accuracy iterative use of sla_REFRO should be considered.
+ </DL></DL>
+<BR> <HR>
+<A NAME="tex2html2106" HREF="node169.html">
+<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next_motif.gif"></A> 
+<A NAME="tex2html2104" HREF="node13.html">
+<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up_motif.gif"></A> 
+<A NAME="tex2html2098" HREF="node167.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="tex2html2107" HREF="node169.html">SLA_REFZ - Apply Refraction to ZD</A>
+<BR>
+<B>Up:</B> <A NAME="tex2html2105" HREF="node13.html">SUBPROGRAM SPECIFICATIONS</A>
+<BR>
+<B> Previous:</B> <A NAME="tex2html2099" HREF="node167.html">SLA_REFRO - Refraction</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>
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/node168.html
download	calfuse-d54fe7c1f704a63824c5bfa0ece65245572e9b27.tar.gz