<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> <!--Converted with LaTeX2HTML 98.1p1 release (March 2nd, 1998) originally 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 Lippmann, Marek Rouchal, Martin Wilck and others --> <HTML> <HEAD> <TITLE>Determination of the Dispersion Coefficients</TITLE> <META NAME="description" CONTENT="Determination of the Dispersion Coefficients"> <META NAME="keywords" CONTENT="vol2"> <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="vol2.css"> <LINK REL="next" HREF="node511.html"> <LINK REL="previous" HREF="node509.html"> <LINK REL="up" HREF="node507.html"> <LINK REL="next" HREF="node511.html"> </HEAD> <BODY > <!--Navigation Panel--> <A NAME="tex2html7831" HREF="node511.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html7828" HREF="node507.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html7822" HREF="node509.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html7830" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="icons.gif/contents_motif.gif"></A> <BR> <B> Next:</B> <A NAME="tex2html7832" HREF="node511.html">Possible Graphical Verifications</A> <B> Up:</B> <A NAME="tex2html7829" HREF="node507.html">Getting the Dispersion Solution</A> <B> Previous:</B> <A NAME="tex2html7823" HREF="node509.html">Line Identification</A> <BR> <BR> <!--End of Navigation Panel--> <H3><A NAME="SECTION003034300000000000000"> Determination of the Dispersion Coefficients</A> </H3> <P> The command <TT>CALIBRATE/LONG</TT> determines the dispersion relation for each row of the spectrum. In addition, a bivariate dispersion relation is computed if the keyword <!-- MATH: $\fbox{TWODOPT}$ --> <IMG WIDTH="133" HEIGHT="29" ALIGN="BOTTOM" BORDER="0" SRC="img1034.gif" ALT="\fbox{TWODOPT}"> is set to <TT>YES</TT>, as in: <BR> <BR> Midas...> <TT>SET/LONG TWODOPT=YES</TT> <BR> Midas...> <TT>CALIBRATE/LONG</TT> <BR> <P> The command <TT>CALIBRATE/LONG</TT> determines row-by-row polynomial solutions of degree <!-- MATH: $\fbox{DCX(1)}$ --> <IMG WIDTH="90" HEIGHT="36" ALIGN="BOTTOM" BORDER="0" SRC="img1035.gif" ALT="\fbox{DCX(1)}"> stored in the table <B>coerbr.tbl</B> and fits a 2-D polynomial of degree <!-- MATH: $\fbox{DCX(1),DCX(2)}$ --> <IMG WIDTH="174" HEIGHT="36" ALIGN="BOTTOM" BORDER="0" SRC="img1036.gif" ALT="\fbox{DCX(1),DCX(2)}"> to the lines with entries in columns :X, :Y, and :WAVE of table <B>line.tbl</B>. The coefficients of the 2D polynomial are stored in the keyword <!-- MATH: $\fbox{KEYLONGD}$ --> <IMG WIDTH="143" HEIGHT="29" ALIGN="BOTTOM" BORDER="0" SRC="img1037.gif" ALT="\fbox{KEYLONGD}">. The program performs a final oulier rejection which eliminates all lines with residuals larger than <!-- MATH: $\fbox{TOL}$ --> <IMG WIDTH="60" HEIGHT="29" ALIGN="BOTTOM" BORDER="0" SRC="img1038.gif" ALT="\fbox{TOL}"> pixels (if <TT>TOL</TT> is positive). However the minimum number of lines in any given row will be <!-- MATH: $\fbox{DCX(1)}$ --> <IMG WIDTH="90" HEIGHT="36" ALIGN="BOTTOM" BORDER="0" SRC="img1039.gif" ALT="\fbox{DCX(1)}">+2. If this number cannot be obtained, a polynomial of lower order will be fitted. Three more columns are added to the table <B>line.tbl</B>: <P> <TABLE CELLPADDING=3> <TR><TD ALIGN="LEFT"> </TD> <TD ALIGN="LEFT"> </TD> </TR> <TR><TD ALIGN="LEFT">:WAVE</TD> <TD ALIGN="LEFT">identified wavelength</TD> </TR> <TR><TD ALIGN="LEFT">:WAVEC</TD> <TD ALIGN="LEFT">wavelength computed from polynomial fit</TD> </TR> <TR><TD ALIGN="LEFT">:RESIDUAL</TD> <TD ALIGN="LEFT">(= :WAVEC - :WAVE) Residual of polynomial fit from</TD> </TR> <TR><TD ALIGN="LEFT"> </TD> <TD ALIGN="LEFT">the tabulated wavelength)</TD> </TR> </TABLE> <P> <BLOCKQUOTE> <DIV ALIGN="CENTER"> <B>Note</DIV> <I>For a proper calibration, images should preferably have positive step descriptors and the wavelength should increase from left to right.</I></B></BLOCKQUOTE> <P> <HR> <!--Navigation Panel--> <A NAME="tex2html7831" HREF="node511.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html7828" HREF="node507.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html7822" HREF="node509.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html7830" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="icons.gif/contents_motif.gif"></A> <BR> <B> Next:</B> <A NAME="tex2html7832" HREF="node511.html">Possible Graphical Verifications</A> <B> Up:</B> <A NAME="tex2html7829" HREF="node507.html">Getting the Dispersion Solution</A> <B> Previous:</B> <A NAME="tex2html7823" HREF="node509.html">Line Identification</A> <!--End of Navigation Panel--> <ADDRESS> <I>Petra Nass</I> <BR><I>1999-06-15</I> </ADDRESS> </BODY> </HTML>