<!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>Flux Calibration and Extinction Correction</TITLE> <META NAME="description" CONTENT="Flux Calibration and Extinction Correction"> <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="node135.html"> <LINK REL="previous" HREF="node133.html"> <LINK REL="up" HREF="node133.html"> <LINK REL="next" HREF="node135.html"> </HEAD> <BODY > <!--Navigation Panel--> <A NAME="tex2html3115" HREF="node135.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html3112" HREF="node133.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html3106" HREF="node133.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html3114" 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="tex2html3116" HREF="node135.html">Airmass Calculation</A> <B> Up:</B> <A NAME="tex2html3113" HREF="node133.html">Flux Calibration</A> <B> Previous:</B> <A NAME="tex2html3107" HREF="node133.html">Flux Calibration</A> <BR> <BR> <!--End of Navigation Panel--> <H2><A NAME="SECTION001051000000000000000"> Flux Calibration and Extinction Correction</A> </H2> <P> To calibrate the chromatic response, observations of a standard star (preferably more than one) are needed, for which the absolute fluxes are known. The spectral response curve of the instrument can then be determined with the command <TT>RESPONSE/LONG</TT>, and absolute fluxes for the objects of interest are obtained with <TT>CALIBRATE/FLUX</TT>. The extinction correction must previously be done in a separate step with the command <TT>EXTINCTION/LONG</TT>. <P> An alternative procedure, if no standard star spectrum is available, is the normalisation<A NAME="5884"> </A> of the continuum<A NAME="5885"> </A> as described below. <P> <BR><HR> <ADDRESS> <I>Petra Nass</I> <BR><I>1999-06-15</I> </ADDRESS> </BODY> </HTML>
