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0001 <sect1 id="tool-aavso">
0002 
0003 <sect1info>
0004 <author>
0005 <firstname>Aaron</firstname>
0006 <surname>Price</surname>
0007 <affiliation><address>
0008 <email>aavso@aavso.org</email>
0009 </address></affiliation>
0010 </author>
0011 </sect1info>
0012 
0013 <title>AAVSO Light Curves</title>
0014 <indexterm><primary>Tools</primary>
0015 <secondary>AAVSO Lightcurve Generator</secondary>
0016 </indexterm>
0017 
0018 <screenshot>
0019 <screeninfo>
0020 The AAVSO Lightcurves Tool
0021 </screeninfo>
0022 <mediaobject>
0023   <imageobject>
0024     <imagedata fileref="aavso.png" format="PNG"/>
0025   </imageobject>
0026   <textobject>
0027     <phrase>AAVSO Lightcurves</phrase>
0028   </textobject>
0029 </mediaobject>
0030 </screenshot>
0031 
0032 <sect2 id="aavso-intro">
0033 <title>Introduction</title>
0034 <para>
0035 &kstars; can display light curves for variable stars from the observing
0036 program of the <ulink url="https://www.aavso.org">American Association
0037 of Variable Star Observers</ulink> (<abbrev>AAVSO</abbrev>).  This
0038 program monitors over 6,000 variable stars and consists of 10 million
0039 observations going back almost a century.  &kstars; downloads the very
0040 latest data directly from the <abbrev>AAVSO</abbrev> database via the
0041 Internet, so a network connection is required to use this tool.
0042 </para>
0043 <para>
0044 To use the tool, select a variable star either by
0045 <firstterm>designation</firstterm> or name in the left panel, and
0046 set the start and end dates to be plotted.  In the right panel,
0047 select the type of data that should be plotted (see below).  When you have
0048 made you selections, press the <guibutton>Retrieve Curve</guibutton>
0049 button.  &kstars; will automatically connect to the AAVSO server,
0050 which will generate the lightcurve plot and send it to your computer for
0051 display.  A sample lightcurve plot is shown below:
0052 </para>
0053 
0054 <screenshot>
0055 <screeninfo>
0056 A Sample Lightcurve
0057 </screeninfo>
0058 <mediaobject>
0059   <imageobject>
0060     <imagedata fileref="lightcurve.png" format="PNG"/>
0061   </imageobject>
0062   <textobject>
0063     <phrase>Sample Lightcurve</phrase>
0064   </textobject>
0065 </mediaobject>
0066 </screenshot>
0067 
0068 <para>
0069 Please not these light curves should <emphasis>NEVER</emphasis> be used
0070 in research, papers, presentations, publications, &etc; They are only
0071 meant to be used as a source of info for &kstars;. They have not been
0072 validated and passed the <abbrev>AAVSO</abbrev>'s strict quality control
0073 measures. We will be glad to give you good raw data simply by requesting
0074 it at <ulink url="http://www.aavso.org/adata/onlinedata/">http://www.aavso.org/adata/onlinedata/</ulink>.
0075 </para>
0076 <!-- broken link in 4.7 -->
0077 <para>
0078 Specific questions about the data in the light curves can be sent to
0079 <email>aavso@aavso.org</email>.
0080 </para>
0081 </sect2>
0082 
0083 <sect2 id="aavso-about">
0084 <title>About Variable Stars</title>
0085 <para>
0086 <firstterm>Variable stars</firstterm> are stars that change in
0087 brightness.  A <firstterm>light curve</firstterm> is a plot of a
0088 variable star's brightness over time. By looking at a light curve you
0089 can see how the star has behaved in the past and try to predict how it
0090 will behave in the future. Astronomers also use this data to model
0091 astrophysical processes in the star. This important to help us
0092 understand how stars work.
0093 </para>
0094 </sect2>
0095 
0096 <sect2 id="aavso-data">
0097 <title>The Data</title>
0098 
0099 <para>
0100 Here is a summary of the various types of data available in the light
0101 curves:
0102 
0103 <itemizedlist>
0104 <listitem><para><firstterm>Visual Observation</firstterm>:
0105 This is an observation of a variable star by an observer with a
0106 regular telescope.  It means that an observer saw the star at Y
0107 brightness on X date and time.</para></listitem>
0108 
0109 <listitem><para><firstterm>Fainter than</firstterm>:
0110 Sometimes the star is too faint to be seen by the observer. When that
0111 happens, the observer reports the faintest star seen in the field.
0112 These are called <quote>fainter thans</quote> because the variable star
0113 was fainter than the brightness reported.</para></listitem>
0114 
0115 <listitem><para><firstterm>Average</firstterm>:
0116 This is a computed running average of all the data reported. The
0117 <firstterm>bin</firstterm> number tells the computer how many days to
0118 use in each average calculation. This will need to be adjusted based on
0119 the frequency of observations. The error bars represent the 1 sigma
0120 standard deviation of error.</para></listitem>
0121 
0122 <listitem><para><firstterm>CCDV</firstterm>:
0123 These are observations reported using a <abbrev>CCD</abbrev> with a
0124 Johnson <abbrev>V</abbrev> filter.  <abbrev>CCDV</abbrev> observations
0125 tend to be more accurate than visual (but not
0126 always).</para></listitem>
0127 
0128 <listitem><para><firstterm>CCDB</firstterm>:
0129 <abbrev>CCD</abbrev> observations with a Johnson <abbrev>B</abbrev>
0130 filter.</para></listitem>
0131 
0132 <listitem><para><firstterm>CCDI</firstterm>:
0133 <abbrev>CCD</abbrev> observations with a Cousins <abbrev>Ic</abbrev>
0134 filter.</para></listitem>
0135 
0136 <listitem><para><firstterm>CCDR</firstterm>:
0137 <abbrev>CCD</abbrev> observations with a Cousins <abbrev>R</abbrev>
0138 filter.</para></listitem>
0139 
0140 <listitem><para><firstterm>Discrepant Data</firstterm>:
0141 This is data that has been flagged by an <abbrev>AAVSO</abbrev> staff
0142 member as being discrepant following <abbrev>HQ</abbrev> rules for
0143 data validation. Contact <email>aavso@aavso.org</email> for more
0144 information.</para></listitem>
0145 
0146 <listitem><para><firstterm>Dates</firstterm>:
0147 The observational database the light curves are based on is updated
0148 every 10 minutes so you can get data in near real-time. Right now
0149 light curve data is only available back to 1961, but this will likely
0150 be expanded further back in time in the future.</para></listitem>
0151 
0152 </itemizedlist>
0153 </para>
0154 </sect2>
0155 
0156 <sect2 id="aavso-update">
0157 <title>Updating your local copy of Variable Stars</title>
0158 <para>
0159 The <abbrev>AAVSO</abbrev> publishes the <!-- broken link in 4.7 -->
0160 <ulink url="http://www.aavso.org/valnam.txt">full list of variable
0161 stars</ulink> in their monitoring program.  This file is updated
0162 monthly with newly discovered variable stars.  To sync the list that
0163 &kstars; uses with the <abbrev>AAVSO</abbrev> master list, click
0164 on the <guibutton>Update List</guibutton> button in the
0165 <abbrev>AAVSO</abbrev> dialog.  &kstars; will then attempt to
0166 connect to the <abbrev>AAVSO</abbrev> database and download the
0167 latest list.
0168 </para>
0169 <note>
0170 <para>
0171 The customized data stream provided by the AAVSO was implemented for
0172 &kstars; by Aaron Price.  Thank you, Aaron!
0173 </para>
0174 </note>
0175 </sect2>
0176 </sect1>
0177