<!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>A modern two-channel photometer</TITLE> <META NAME="description" CONTENT="A modern two-channel photometer"> <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="node632.html"> <LINK REL="previous" HREF="node630.html"> <LINK REL="up" HREF="node628.html"> <LINK REL="next" HREF="node632.html"> </HEAD> <BODY > <!--Navigation Panel--> <A NAME="tex2html9388" HREF="node632.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html9385" HREF="node628.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html9379" HREF="node630.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html9387" 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="tex2html9389" HREF="node632.html">CCD photometry</A> <B> Up:</B> <A NAME="tex2html9386" HREF="node628.html">Sample instrument files</A> <B> Previous:</B> <A NAME="tex2html9380" HREF="node630.html">A modern single-channel photometer</A> <BR> <BR> <!--End of Navigation Panel--> <H3><A NAME="SECTION003257300000000000000"> </A> <A NAME="sect-2chan"> </A> <BR> A modern two-channel photometer </H3> Next, consider a more elaborate UBVRI photometer with two channels (a ``red'' and a ``blue'' tube). We suppose it has separate filter wheels in the two beams; the first filter wheel contains the UBV filters, and the second has the R and I filters. Filter position 0 in each wheel is opaque; note that we need separate DARK codes for the two channels. Red leaks are blocked, and filter temperatures are measured. <P> If the filter wheels had been in series instead of in separate beams, the unused wheel would have to be set to a clear position, instead of the ``any'' entered in the first five lines of Table <A HREF="node630.html#tbl:2-chan-example">I.15</A>. <P> Because we have two detectors, the NDETUSED column is mandatory; see Table <A HREF="node630.html#tbl:2-chan-example">I.15</A>. In our example, the ``blue'' tube is uncooled, but its temperature is measured; while the ``red'' tube is cooled with dry ice. Both run in charge-integration mode. <P> <BR> <DIV ALIGN="CENTER"><A NAME="30606"> </A> <TABLE> <CAPTION><STRONG>Table:</STRONG> Instrument table file for a simple CCD setup</CAPTION> <TR><TD> <P> Descriptor values: <P> <B>NFILTCAR</B> = 1 <P> <B>NDETS</B> = 1 <P> <B>FILTSTAT</B> = <TT>DOME</TT> <P> <B>FILTCAT</B> = <TT>' '</TT> (blank string) <P> <B>CONDITION</B> = <TT>AVERAGE</TT> <P> <P> <DIV ALIGN="CENTER"> Passband sub-table<TABLE CELLPADDING=3 BORDER="1"> <TR><TD ALIGN="CENTER">NBAND</TD> <TD ALIGN="LEFT">BAND</TD> <TD ALIGN="CENTER">FILTCODE_1</TD> <TD ALIGN="LEFT">REDLEAK</TD> </TR> <TR><TD ALIGN="CENTER">---</TD> <TD ALIGN="LEFT">--</TD> <TD ALIGN="CENTER">-----</TD> <TD ALIGN="LEFT">----</TD> </TR> <TR><TD ALIGN="CENTER">1</TD> <TD ALIGN="LEFT">B</TD> <TD ALIGN="CENTER">B</TD> <TD ALIGN="LEFT">BLOCKED</TD> </TR> <TR><TD ALIGN="CENTER">2</TD> <TD ALIGN="LEFT">V</TD> <TD ALIGN="CENTER">V</TD> <TD ALIGN="LEFT">BLOCKED</TD> </TR> </TABLE> <P> <P> Detector sub-table<TABLE CELLPADDING=3 BORDER="1"> <TR><TD ALIGN="CENTER">NDET</TD> <TD ALIGN="CENTER">DET</TD> <TD ALIGN="CENTER">BLUERESP</TD> <TD ALIGN="CENTER">COOLING</TD> <TD ALIGN="CENTER">DETTEMP</TD> </TR> <TR><TD ALIGN="CENTER">--</TD> <TD ALIGN="CENTER">----</TD> <TD ALIGN="CENTER">----</TD> <TD ALIGN="CENTER">-----</TD> <TD ALIGN="CENTER">----</TD> </TR> <TR><TD ALIGN="CENTER">1</TD> <TD ALIGN="CENTER">SILICON</TD> <TD ALIGN="CENTER">FRONT</TD> <TD ALIGN="CENTER">REGULATED</TD> <TD ALIGN="CENTER">180.</TD> </TR> </TABLE> </DIV> <A NAME="tbl:ccd-example"> </A></TD></TR> </TABLE> </DIV> <BR> <P> <HR> <!--Navigation Panel--> <A NAME="tex2html9388" HREF="node632.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html9385" HREF="node628.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html9379" HREF="node630.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html9387" 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="tex2html9389" HREF="node632.html">CCD photometry</A> <B> Up:</B> <A NAME="tex2html9386" HREF="node628.html">Sample instrument files</A> <B> Previous:</B> <A NAME="tex2html9380" HREF="node630.html">A modern single-channel photometer</A> <!--End of Navigation Panel--> <ADDRESS> <I>Petra Nass</I> <BR><I>1999-06-15</I> </ADDRESS> </BODY> </HTML>
