Looking at data
===============

You can use the `HiPERCAM pipeline reduction software
<http://deneb.astro.warwick.ac.uk/phsaap/hipercam/docs/html/>`_ to
look at data either in real-time during the night or when not
observing.

To run the HiPERCAM pipeline reduction software, simply open an xterm
on the DRPC and then ``cd /home/observer/reduce/yyyy_mm_dd``, where
``yyyy_mm_dd`` is the current date. If this sub-directory does not exist,
create it. All data reduction on this date should be performed in this
directory, as the reduction files are archived along with the
corresponding raw data on each night (see :ref:`Archiving data
<archiving>`).

To run one of the HiPERCAM pipeline reduction scripts, simply type its
name. For example, typing ``rtplot`` provides a real-time plot of the
images as they are obtained with HiPERCAM. Note that if the observing
system is not running, the HiPERCAM pipeline reduction software will
not be able to access the raw data files from the file server on the
rack PC. If you wish to run the file server without starting up the
observing system (see :ref:`Software startup <software>`), open an
xterm on the rack PC and type: ``fileserver --dir
/insroot/insuser/SYSTEM/DETDATA/``.

To obtain a light curve in real time, only four commands need to be run:

1. ``averun`` - averages the frames in a run to improve the
   signal-to-noise ratio of the image. This is of use when trying to define
   apertures around faint stars.

2. ``setaper`` - defines software apertures around the target and comparison
   stars and sky in order to perform differential photometry.

3. ``genred`` - generates a ``reduce`` file, which defines all of the
   parameters for the photometric reduction and the display of the
   results.

4. ``reduce`` - performs the photometric reduction and displays the results.
   
When prompted to do so, please name all of the output files written by
the above routines as the run number. So, for example, when reducing
the raw data file ``run0012.fits``, ``averun`` should write the file
``run0012.hcm``, ``setaper`` should write the file ``run0012.ape``,
``genred`` should write the file ``run0012.red`` and ``reduce`` should
write the file ``run0012.log``. Following this convention makes it much
easier for users of the archive to inspect the reduced data. 

The DRPC desktop should look like the screenshot below when
observing. It is recommended that you open all of the windows
described above in the top-middle virtual desktop of the DRPC.

.. image:: photos/reduce_screenshot.png
    :width: 75%