<!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>Column label: DIAM</TITLE> <META NAME="description" CONTENT="Column label: DIAM"> <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="node572.html"> <LINK REL="previous" HREF="node570.html"> <LINK REL="up" HREF="node569.html"> <LINK REL="next" HREF="node572.html"> </HEAD> <BODY > <!--Navigation Panel--> <A NAME="tex2html8658" HREF="node572.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html8655" HREF="node569.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html8649" HREF="node570.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html8657" 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="tex2html8659" HREF="node572.html">Column label: LON</A> <B> Up:</B> <A NAME="tex2html8656" HREF="node569.html">Permanent telescope parameters</A> <B> Previous:</B> <A NAME="tex2html8650" HREF="node570.html">Column label: TELESCOP</A> <BR> <BR> <!--End of Navigation Panel--> <H2><A NAME="SECTION003232000000000000000"> Column label: DIAM</A> </H2> <P> This is the actual diameter in meters of the telescope entrance pupil. For small telescopes, it provides significantly more precision than the rounded value embedded in the telescope name. For large telescopes with segmented apertures, it will suffice to specify the equivalent diameter corresponding to the total collecting area. (This will give the right value for the photon noise, but not for the scintillation noise. Most segmented apertures are on large telescopes whose scintillation noise is negligible anyway, so this is not a significant problem.) <P> <BR><HR> <ADDRESS> <I>Petra Nass</I> <BR><I>1999-06-15</I> </ADDRESS> </BODY> </HTML>
