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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/node16.html | |
| download | calfuse-d54fe7c1f704a63824c5bfa0ece65245572e9b27.tar.gz | |
Initial commit
Diffstat (limited to 'src/slalib/sun67.htx/node16.html')
| -rw-r--r-- | src/slalib/sun67.htx/node16.html | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/src/slalib/sun67.htx/node16.html b/src/slalib/sun67.htx/node16.html new file mode 100644 index 0000000..682e1dd --- /dev/null +++ b/src/slalib/sun67.htx/node16.html @@ -0,0 +1,121 @@ +<!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_AIRMAS - Air Mass</TITLE> +<META NAME="description" CONTENT="SLA_AIRMAS - Air Mass"> +<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="node17.html"> +<LINK REL="previous" HREF="node15.html"> +<LINK REL="up" HREF="node13.html"> +<LINK REL="next" HREF="node17.html"> +</HEAD> +<BODY > +<BR> <HR> +<A NAME="tex2html586" HREF="node17.html"> +<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next_motif.gif"></A> +<A NAME="tex2html584" HREF="node13.html"> +<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up_motif.gif"></A> +<A NAME="tex2html578" HREF="node15.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="tex2html587" HREF="node17.html">SLA_ALTAZ - Velocities etc. for Altazimuth Mount</A> +<BR> +<B>Up:</B> <A NAME="tex2html585" HREF="node13.html">SUBPROGRAM SPECIFICATIONS</A> +<BR> +<B> Previous:</B> <A NAME="tex2html579" HREF="node15.html">SLA_AFIN - Sexagesimal character string to angle</A> +<BR> <HR> <P> +<P><!--End of Navigation Panel--> +<H2><A NAME="SECTION00043000000000000000">SLA_AIRMAS - Air Mass</A> +<A NAME="xref_SLA_AIRMAS"> </A><A NAME="SLA_AIRMAS"> </A> +</H2> + <DL> +<DT><STRONG>ACTION:</STRONG> +<DD>Air mass at given zenith distance (double precision). +<DT><STRONG>CALL:</STRONG> +<DD><TT>D = sla_AIRMAS (ZD)</TT> +<P> </DL> +<P> <DL> +<DT><STRONG>GIVEN:</STRONG> +<DD> +<BR> +<TABLE CELLPADDING=3> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>ZD</EM></TD> +<TH ALIGN="LEFT"><B>D</B></TH> +<TD ALIGN="LEFT" NOWRAP>observed zenith distance (radians)</TD> +</TR> +</TABLE></DL> +<P> <DL> +<DT><STRONG>RETURNED:</STRONG> +<DD> +<BR> +<TABLE CELLPADDING=3> +<TR VALIGN="TOP"><TD ALIGN="LEFT"><EM>sla_AIRMAS</EM></TD> +<TH ALIGN="LEFT"><B>D</B></TH> +<TD ALIGN="LEFT" NOWRAP>air mass (1 at zenith)</TD> +</TR> +</TABLE></DL> +<P> <DL> +<DT><STRONG>NOTES:</STRONG> +<DD><DL COMPACT> +<DT>1. +<DD>The <I>observed</I> zenith distance referred to above means +``as affected by refraction''. +<DT>2. +<DD>The routine uses Hardie's (1962) polynomial fit to Bemporad's + data for the relative air mass, <I>X</I>, in units of thickness at the + zenith as tabulated by Schoenberg (1929). This is adequate for all + normal needs as it is accurate to better than + 0.1% up to <I>X</I> = 6.8 and better than 1% up to <I>X</I> = 10. + Bemporad's tabulated values are unlikely to be trustworthy + to such accuracy + because of variations in density, pressure and other + conditions in the atmosphere from those assumed in his work. + <DT>3. +<DD>The sign of the ZD is ignored. + <DT>4. +<DD>At zenith distances greater than about <IMG WIDTH="56" HEIGHT="27" ALIGN="MIDDLE" BORDER="0" + SRC="img8.gif" + ALT="$\zeta = 87^{\circ}$"> the + air mass is held constant to avoid arithmetic overflows. + </DL></DL> +<P> <DL> +<DT><STRONG>REFERENCES:</STRONG> +<DD><DL COMPACT> +<DT>1. +<DD>Hardie, R.H., 1962, in <I>Astronomical Techniques</I> +ed. W.A. Hiltner, University of Chicago Press, p180. +<DT>2. +<DD>Schoenberg, E., 1929, Hdb. d. Ap., + Berlin, Julius Springer, 2, 268. + </DL></DL> +<BR> <HR> +<A NAME="tex2html586" HREF="node17.html"> +<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next_motif.gif"></A> +<A NAME="tex2html584" HREF="node13.html"> +<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up_motif.gif"></A> +<A NAME="tex2html578" HREF="node15.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="tex2html587" HREF="node17.html">SLA_ALTAZ - Velocities etc. for Altazimuth Mount</A> +<BR> +<B>Up:</B> <A NAME="tex2html585" HREF="node13.html">SUBPROGRAM SPECIFICATIONS</A> +<BR> +<B> Previous:</B> <A NAME="tex2html579" HREF="node15.html">SLA_AFIN - Sexagesimal character string to angle</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> |