<!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>Combining Flat Fields</TITLE> <META NAME="description" CONTENT="Combining Flat Fields"> <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="node48.html"> <LINK REL="previous" HREF="node46.html"> <LINK REL="up" HREF="node42.html"> <LINK REL="next" HREF="node48.html"> </HEAD> <BODY > <!--Navigation Panel--> <A NAME="tex2html2032" HREF="node48.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html2029" HREF="node42.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html2023" HREF="node46.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html2031" 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="tex2html2033" HREF="node48.html">Combining Sky Frames</A> <B> Up:</B> <A NAME="tex2html2030" HREF="node42.html">Preparing Your Calibration Frames</A> <B> Previous:</B> <A NAME="tex2html2024" HREF="node46.html">Combining Dark Frames</A> <BR> <BR> <!--End of Navigation Panel--> <H2><A NAME="SECTION00685000000000000000"> </A> <A NAME="ccd:combining-flat-fields"> </A> <BR> Combining Flat Fields </H2> In combining the flat field frames the filter type is of importance. Hence, the combining command will check for consistency of the keyword containing the filter type. The combining input parameters can be set up in the flat parameter table, similar to the dark frames. Table <A HREF="node47.html#ccd:flat-keywords">3.6</A> show the default keyword settings. <P> <BR> <DIV ALIGN="CENTER"><A NAME="1875"> </A> <TABLE> <CAPTION><STRONG>Table 3.6:</STRONG> Keywords for combining flat field calibration frames</CAPTION> <TR><TD> <DIV ALIGN="CENTER"> <TABLE CELLPADDING=3 BORDER="1" ALIGN="CENTER"> <TR><TH ALIGN="LEFT"><B>Keyword </B></TH> <TH ALIGN="LEFT"><B>Content </B></TH> <TH ALIGN="LEFT"><B>Default </B></TH> <TH ALIGN="LEFT"><B>Description </B></TH> </TR> <TR><TD ALIGN="LEFT"><TT> CCD_IN</TT></TD> <TD ALIGN="LEFT">input name</TD> <TD ALIGN="LEFT">?</TD> <TD ALIGN="LEFT">table of input frames</TD> </TR> <TR><TD ALIGN="LEFT"><TT> FF_TYP</TT></TD> <TD ALIGN="LEFT">descriptor value</TD> <TD ALIGN="LEFT">*</TD> <TD ALIGN="LEFT">exposure type to check, if any</TD> </TR> <TR><TD ALIGN="LEFT"><TT> FF_SIG</TT></TD> <TD ALIGN="LEFT">yes|no</TD> <TD ALIGN="LEFT">no</TD> <TD ALIGN="LEFT">create sigma image</TD> </TR> <TR><TD ALIGN="LEFT"><TT> FF_MET</TT></TD> <TD ALIGN="LEFT">comb. method</TD> <TD ALIGN="LEFT">avsigcl</TD> <TD ALIGN="LEFT">type of combining operation</TD> </TR> <TR><TD ALIGN="LEFT"><TT> FF_DEL</TT></TD> <TD ALIGN="LEFT">yes|no</TD> <TD ALIGN="LEFT">no</TD> <TD ALIGN="LEFT">delete cal. frames afterwards</TD> </TR> <TR><TD ALIGN="LEFT"><TT> FF_STA</TT></TD> <TD ALIGN="LEFT">mean|median|mode</TD> <TD ALIGN="LEFT">mode</TD> <TD ALIGN="LEFT">correct. by Mode/Median/Mean</TD> </TR> <TR><TD ALIGN="LEFT"><TT> FF_EXP</TT></TD> <TD ALIGN="LEFT">yes|no</TD> <TD ALIGN="LEFT">yes</TD> <TD ALIGN="LEFT">scale by exposure time</TD> </TR> <TR><TD ALIGN="LEFT"><TT> FF_SCA</TT></TD> <TD ALIGN="LEFT">yes|no</TD> <TD ALIGN="LEFT">no</TD> <TD ALIGN="LEFT">scale by MMM</TD> </TR> <TR><TD ALIGN="LEFT"><TT> FF_OFF</TT></TD> <TD ALIGN="LEFT">yes|no</TD> <TD ALIGN="LEFT">no</TD> <TD ALIGN="LEFT">add offset obtained from MMM</TD> </TR> <TR><TD ALIGN="LEFT"><TT> FF_WEI</TT></TD> <TD ALIGN="LEFT">yes|no</TD> <TD ALIGN="LEFT">yes</TD> <TD ALIGN="LEFT">use a weighted average</TD> </TR> <TR><TD ALIGN="LEFT"><TT> FF_SEC</TT></TD> <TD ALIGN="LEFT">area</TD> <TD ALIGN="LEFT">[<,<:>,>]</TD> <TD ALIGN="LEFT">area for computing MMM</TD> </TR> <TR><TD ALIGN="LEFT"><TT> FF_RAN</TT></TD> <TD ALIGN="LEFT">real,real</TD> <TD ALIGN="LEFT">-99999,99999</TD> <TD ALIGN="LEFT">valid pixel range</TD> </TR> <TR><TD ALIGN="LEFT"><TT> FF_CLP</TT></TD> <TD ALIGN="LEFT">real</TD> <TD ALIGN="LEFT">3.,3.</TD> <TD ALIGN="LEFT">low/high sigma clipping factor</TD> </TR> <TR><TD ALIGN="LEFT"><TT> FF_NUL</TT></TD> <TD ALIGN="LEFT">real</TD> <TD ALIGN="LEFT"><TT> NULL(2)</TT></TD> <TD ALIGN="LEFT">value for rejections</TD> </TR> </TABLE></DIV> <A NAME="ccd:flat-keywords"> </A> </TD></TR> </TABLE> </DIV> <BR> <P> <HR> <!--Navigation Panel--> <A NAME="tex2html2032" HREF="node48.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html2029" HREF="node42.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html2023" HREF="node46.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html2031" 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="tex2html2033" HREF="node48.html">Combining Sky Frames</A> <B> Up:</B> <A NAME="tex2html2030" HREF="node42.html">Preparing Your Calibration Frames</A> <B> Previous:</B> <A NAME="tex2html2024" HREF="node46.html">Combining Dark Frames</A> <!--End of Navigation Panel--> <ADDRESS> <I>Petra Nass</I> <BR><I>1999-06-15</I> </ADDRESS> </BODY> </HTML>
