<!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>Error estimates</TITLE> <META NAME="description" CONTENT="Error estimates"> <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="previous" HREF="node647.html"> <LINK REL="up" HREF="node640.html"> <LINK REL="next" HREF="node649.html"> </HEAD> <BODY > <!--Navigation Panel--> <A NAME="tex2html9593" HREF="node649.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html9590" HREF="node640.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html9586" HREF="node647.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html9592" 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="tex2html9594" HREF="node649.html">Bibliography</A> <B> Up:</B> <A NAME="tex2html9591" HREF="node640.html">Additional information</A> <B> Previous:</B> <A NAME="tex2html9587" HREF="node647.html">Seeing</A> <BR> <BR> <!--End of Navigation Panel--> <H3><A NAME="SECTION003262800000000000000"> Error estimates</A> </H3> Data extracted from CCD frames may be accompanied by error estimates, which can be used in determining weights in the general solution. These should be in the same intensity units as the data in the SIGNAL column. The same format should be used as for the SIGNAL. The column label for estimated errors is ESTERR. <P> This column should not be used for ordinary photometric data (i.e., do not put estimates of ``photon noise'' here). It should only be used when an independent estimate of noise is available <I>in addition to</I> the information in the other columns. <P> If the data were expressed as magnitudes (column RAWMAG), any error estimates should also be in magnitudes. <P> <BR><HR> <ADDRESS> <I>Petra Nass</I> <BR><I>1999-06-15</I> </ADDRESS> </BODY> </HTML>
