<!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>Introduction</TITLE> <META NAME="description" CONTENT="Introduction"> <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="node84.html"> <LINK REL="previous" HREF="node82.html"> <LINK REL="up" HREF="node82.html"> <LINK REL="next" HREF="node84.html"> </HEAD> <BODY > <!--Navigation Panel--> <A NAME="tex2html2487" HREF="node84.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html2484" HREF="node82.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html2478" HREF="node82.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html2486" 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="tex2html2488" HREF="node84.html">Theory</A> <B> Up:</B> <A NAME="tex2html2485" HREF="node82.html">Crowded Field Photometry</A> <B> Previous:</B> <A NAME="tex2html2479" HREF="node82.html">Crowded Field Photometry</A> <BR> <BR> <!--End of Navigation Panel--> <H1><A NAME="SECTION00810000000000000000"> Introduction</A> </H1> This chapter describes the set of commands implemented in MIDAS to do crowded field photometry on digital astronomical images. The package has been developed by <BR> R. Buonanno, G. Buscema, C. Corsi, I. Ferraro, and G. Iannicola, all at the Osservatorio Astronomico di Roma. The package runs as a part of the data reduction system at Rome Observatory and is well known from its name: ROMAFOT. Since in Italian the suffix ``fot'' refers also to the word ``photometry'', the name ROMAFOT was chosen as an easy homophony with DAOPHOT. <P> The idea of ROMAFOT was born (and realised) in the second half of the seventies. The need for such a package has arisen from the technical evolution (for instance the arrival of the PDS etc.) and from the huge amounts of data becoming manageable. A rich bibliography of authors who worked on the same objective (e.g. Newell and O'Neil, 1974 [<A HREF="node119.html#nao:eao">1</A>], Van Altena and Auer, 1975 [<A HREF="node119.html#vaa:ipt">2</A>], Butcher, 1977 [<A HREF="node119.html#but:apj">3</A>], Herzog and Illingworth, 1977 [<A HREF="node119.html#hai:sup">4</A>], Chiu, 1977 [<A HREF="node119.html#chi:ajc">5</A>], Auer and Van Altena, 1978 [<A HREF="node119.html#ava:aja">6</A>] Buonanno et al., 1979 [<A HREF="node119.html#bea:iwi">7</A>], Buonanno et al., 1983 [<A HREF="node119.html#asx:uia">8</A>] Stetson, 1979 [<A HREF="node119.html#ste:ajs">9</A>], Stetson, 1979 [<A HREF="node119.html#ste:sja">10</A>]) shows that efficient handling of digital astronomical images was widely felt for the astronomical community. In addition, since the numerical problem requires very classic solutions, neither the <I>idea</I> nor the <I>solution</I> asks for particular emphasis. <BR> Where ROMAFOT has perhaps merit is in having taken dozens of decisions such as: <UL> <LI>should the sky background be calculated before or together with the star? <LI>which size of the subwindow optimises the ratio photometric quality/computing time? <LI>when should two objects be considered blended and be fitted together? <LI>which is the optimum degree of interaction? </UL> All these choices require experiments, time, and naturally effort. <P> In this description Section <A HREF="node84.html#theory">5.2</A> gives some theoretical background about how ROMAFOT operates. Section <A HREF="node85.html#overview-of-romafot">5.3</A> presents an overview of the commands available in the ROMAFOT context. Section <A HREF="node86.html#how-to-use-romafot">5.4</A> describes the commands in detail. The section is split into a part for the automatic reduction and a part for the more interactive reduction. Finally, Section <A HREF="node118.html#ch05-com-syn">5.5</A> gives a summary of all ROMAFOT commands. <P> <HR> <!--Navigation Panel--> <A NAME="tex2html2487" HREF="node84.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="icons.gif/next_motif.gif"></A> <A NAME="tex2html2484" HREF="node82.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="icons.gif/up_motif.gif"></A> <A NAME="tex2html2478" HREF="node82.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="icons.gif/previous_motif.gif"></A> <A NAME="tex2html2486" 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="tex2html2488" HREF="node84.html">Theory</A> <B> Up:</B> <A NAME="tex2html2485" HREF="node82.html">Crowded Field Photometry</A> <B> Previous:</B> <A NAME="tex2html2479" HREF="node82.html">Crowded Field Photometry</A> <!--End of Navigation Panel--> <ADDRESS> <I>Petra Nass</I> <BR><I>1999-06-15</I> </ADDRESS> </BODY> </HTML>