<!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>Special systems</TITLE> <META NAME="description" CONTENT="Special systems"> <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="node297.html"> <LINK REL="previous" HREF="node295.html"> <LINK REL="up" HREF="node293.html"> <LINK REL="next" HREF="node297.html"> </HEAD> <BODY > <!--Navigation Panel--> <A NAME="tex2html5124" HREF="node297.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html5121" HREF="node293.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html5115" HREF="node295.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html5123" 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="tex2html5125" HREF="node297.html">Marginal nights</A> <B> Up:</B> <A NAME="tex2html5122" HREF="node293.html">Special problems</A> <B> Previous:</B> <A NAME="tex2html5116" HREF="node295.html">Nonlinearity</A> <BR> <BR> <!--End of Navigation Panel--> <H3><A NAME="SECTION001859300000000000000"> Special systems</A> </H3> <P> If you want to either plan or reduce observations made in your own non-standard system, both the planning and the reduction programs let you declare the system as <TT>NONE</TT> or <TT>OTHER</TT>. Use <TT>NONE</TT> when you want to work entirely in the instrumental system, and <TT>OTHER</TT> when you want to use a special system of standard stars. In either case, you will need to specify central wavelengths, bandwidths, and the relation between the passband magnitudes and whatever color indices you use. <P> You can maintain your own files of standard stars for your private system, or for your instrumental system. Sometimes it is convenient to maintain instrumental-system standards, to avoid the information loss of conformity errors, which should be negligible in this case. Instrumental mean values can then be used to determine extinction very accurately. <P> <BR><HR> <ADDRESS> <I>Petra Nass</I> <BR><I>1999-06-15</I> </ADDRESS> </BODY> </HTML>
