<!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>Order Merging</TITLE> <META NAME="description" CONTENT="Order Merging"> <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="node169.html"> <LINK REL="previous" HREF="node165.html"> <LINK REL="up" HREF="node145.html"> <LINK REL="next" HREF="node169.html"> </HEAD> <BODY > <!--Navigation Panel--> <A NAME="tex2html3522" HREF="node169.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html3519" HREF="node145.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html3513" HREF="node167.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html3521" 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="tex2html3523" HREF="node169.html">Implementation</A> <B> Up:</B> <A NAME="tex2html3520" HREF="node145.html">Echelle Spectra</A> <B> Previous:</B> <A NAME="tex2html3514" HREF="node167.html">Fitting the Blaze Function</A> <BR> <BR> <!--End of Navigation Panel--> <H1><A NAME="SECTION001190000000000000000"> Order Merging</A> </H1> Finally, the extracted orders, sampled at constant wavelength steps and corrected for the blaze effect, can be merged into a one dimensional spectrum which is suitable for further analysis. The merging<A NAME="7351"> </A> algorithm computes a weighted average in the overlapping region of adjacent orders. The normalised weight is a linear ramp changing from 0 to 1 in the overlapping region for each of the adjacent orders. Therefore, in the overlapping region of two consecutive orders, the ramp decreases linearly for the `blue' order while it increases linearly for the `red' order. This gives less weight to points near the edges of the orders. It is also possible to extract individual orders and store them in different spectral files for further analysis. The command <TT>MERGE/ECHELLE</TT> performs the merging of the orders. <P> <BR><HR> <ADDRESS> <I>Petra Nass</I> <BR><I>1999-06-15</I> </ADDRESS> </BODY> </HTML>
