<!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>Removing Irrelevant Columns</TITLE> <META NAME="description" CONTENT="Removing Irrelevant Columns"> <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="node446.html"> <LINK REL="previous" HREF="node444.html"> <LINK REL="up" HREF="node441.html"> <LINK REL="next" HREF="node446.html"> </HEAD> <BODY > <!--Navigation Panel--> <A NAME="tex2html7000" HREF="node446.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html6997" HREF="node441.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html6991" HREF="node444.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html6999" 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="tex2html7001" HREF="node446.html">Bias Corrections</A> <B> Up:</B> <A NAME="tex2html6998" HREF="node441.html">CCD Detectors</A> <B> Previous:</B> <A NAME="tex2html6992" HREF="node444.html">Reduction Steps</A> <BR> <BR> <!--End of Navigation Panel--> <H2><A NAME="SECTION002514000000000000000"> Removing Irrelevant Columns</A> </H2> <P> With the ESO CCD systems currently in use, some columns or/and rows are added in electronically and contain no valid data. The command: <BLOCKQUOTE> <TT>EXTRACT/CCD extr_coords [catalog]</TT></BLOCKQUOTE>will remove these columns from all frames in the referenced catalog. The default is the general catalog. This function will slightly speed up subsequent operations and will avoid possible problems with strange pixel values sometimes found in these columns. <P> <BR><HR> <ADDRESS> <I>Petra Nass</I> <BR><I>1999-06-15</I> </ADDRESS> </BODY> </HTML>
