<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Strict//EN"> <html><head> <link rel="stylesheet" type="text/css" href="cmunipack.css"> <title>Finding variables</title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> </head><body><div class="main_head"><p class="head"><a href="index.html">C-Munipack 1.2</a> / <a href="node006.html">User's manual</a></p><h1>Finding variables</h1></div><p>The CCD observation allows to measure brightness of all stars occuring in the field of the telescope. It may happen, that on a series of frames that appart from observed star there occures also another variable star. By the following steps, you can perhaps discover a new variable star.</p><p>The "Find variables" dialog is the useful tool that provides semi-automatic scanning of variable stars in the series of source files. It is based on the relation between the standard deviations of the brightness of the stars and their mean brightness. The program reads all photometry files and compute the mean brightness and standard deviations of brightness of all stars. The algorithm automatically removes stars that are missing on majority of source frames. For the star of lower magnitude the deviation of brightness exhibits higher value than deviation for stars with a higher brightness.</p><p>First follow all steps of observed frames reduction through processing the photometry files. Click on the <tt>Tools</tt> -> <tt>Find variables</tt> item in the main menu. The program computes all stars brightness data at all frames and selects one comparison star. The dialog window opens. At top left area a graph of mag vs. stdev is shown. On the right part the identification chart with variable star marked up is presented. Also the selected star light-curve graph is shown.</p><div class="mediaobject"><img border=0 src="varfind.png" alt="Find variables"/></div><p>Click at any point of the graph left. The program marks the point with red circle with the <tt>var</tt> label. The same way, the corresponding star is marked up on the identification chart. In the bottom part of the dialog window, the light-curve graph of the star is plotted. Sequentially indicate all stars, you suspect to be a variable star.</p><p>The comparison star is marked with green circle with the <tt>comp</tt> label. Although the comparison star is automatically selected, the selection does not need be ideal. To change the comparison star manually, click on <tt>Comp</tt> button on the control panel and select the star on the identification chart. When done, click on the <tt>Var</tt> button to switch back to variable selection mode.</p><p>By the help of the buttons on the panel, the graph, chart or the light-curve can be saved as data or image file.</p></body></html>
