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<div class="section" id="advanced-calibration-scheme">
<span id="index-0"></span><span id="id1"></span><h1>Advanced calibration scheme<a class="headerlink" href="#advanced-calibration-scheme" title="Permalink to this headline">¶</a></h1>
<p>The standard calibration of CCD frames uses single dark frame and single flat frame.
To obtain reasonable results, it is necessary to use dark frame of the same exposure duration
as the scientific images. If you observe several objects during a night and those objects have
different magnitude, different exposure durations are often used. But in this case you will
need to carry out as many sets of dark frames as the number of exposures you have chosen.
This task may be quite time consuming work. This disadvantage can be solved by advanced
calibration, which involves scalable dark frames. The reduction process in this case is a
bit more complicated than standard one, so it is recommended to experienced users only.</p>
<div class="section" id="calibration-procedure">
<span id="index-1"></span><h2>Calibration procedure<a class="headerlink" href="#calibration-procedure" title="Permalink to this headline">¶</a></h2>
<ol class="arabic simple">
<li>Acquire a set of bias frames. They are carried out by the similar way as the
dark frames, the exposure duration should be minimal (zero in ideal case). I used
total number of 90 frames. The bias frames can be reused till some change to the
camera hardware was made, so you need to acquire the set only once.</li>
<li>Each night, acquire the set of dark frames using long exposure duration. It
is recommended to carry out dark frames on the end of observation, when the camera
is enough uniformly cooled. I took ten frames, 120 seconds each.</li>
<li>Open the Muniwin program, open the <em class="guilabel">Tools</em> menu and click on
the <em class="guilabel">Preferences</em> item. Select the <em class="guilabel">Calibration</em>
tab and check the Use advanced calibration scheme option.</li>
<li>Add all bias frames (see step 1) to the table of input files. Convert them to
temporary folder, check and remove all severed frames. Run the Make master-bias frame
tool to make single master bias frame.</li>
<li>Clear the table of input files and add all dark frames (see step 2) to it.
Convert files to the temporary folder, check and remove all severed frames. Open
the Make master-dark frame tool, the dialog window opens. In the dialog, check the
<em class="guilabel">Make scalable dark frame</em> option. Close the dialog by the
<em class="guilabel">OK</em> button.</li>
<li>In the Select a bias-frame dialog, select file, which contains the master bias
frame (see step 4) from the list. Click on the <em class="guilabel">OK</em> button to continue.</li>
<li>In the following dialog select a directory and enter the name of output file
to be saved. Press the <em class="guilabel">Save</em> button.</li>
<li>Clear the table of input files again, add the scientific images to it and convert
them to the temporary folder. Open the <em class="guilabel">Corrections</em> menu and select
the <em class="guilabel">Bias frame</em> item. A new dialog window opens, find and
select the bias frame, which was made in step 4. Next, open the Dark frame dialog and
select the dark frame made in step 7.</li>
<li>Continue in reduction of source images by standard way.</li>
</ol>
</div>
<div class="section" id="remarks">
<h2>Remarks<a class="headerlink" href="#remarks" title="Permalink to this headline">¶</a></h2>
<ul class="simple">
<li>The <span class="target" id="index-2"></span>scalable dark frame is automatically detected using
the information stored in the file header. For all other frames which are not considered to be scalable ones,
the standard calibration is used.</li>
</ul>
<div class="admonition-see-also admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last"><a class="reference internal" href="bias_correction_dialog.html#bias-correction-dialog"><em>Bias correction (dialog)</em></a>, <a class="reference internal" href="master_bias_frame_dialog.html#master-bias-frame-dialog"><em>Master bias frame (dialog)</em></a>, <a class="reference internal" href="dark_correction_dialog.html#dark-correction-dialog"><em>Dark correction (dialog)</em></a>,
<a class="reference internal" href="master_dark_frame_dialog.html#master-dark-frame-dialog"><em>Master dark frame (dialog)</em></a>, <a class="reference internal" href="project_settings_dialog.html#project-settings-dialog"><em>Project settings (dialog)</em></a></p>
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<h3><a href="index.html">Table Of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">Advanced calibration scheme</a><ul>
<li><a class="reference internal" href="#calibration-procedure">Calibration procedure</a></li>
<li><a class="reference internal" href="#remarks">Remarks</a></li>
</ul>
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