ReduceNight


This routine is designed to assist the user when reducing whole nights of observations. It doesn't turn everything into a "black box", but just simpifies the bookkeeping and the repeatability by calling "MIA" with the correct filenames and by storing the results.


  • Reading the data

    First go to a directory where you have permissions to write. Afterwards, start the routine by typing

      reducenight,'<path>'

      Options

     /CALONLYrequired for nights with calibrators only
     /STEPset the spacing between the visibility bins to 1, i.e. maximum sampling

    <path> is the directory containing the data to be reduced. The procedure creates logfiles of this directory with "make_midi_log" and identifies all tracking and photometric files by using the NRTS_MODE keyword. After the identification a window similar to that shown below is displayed. It contains a diagram where all found tracking (top) and photometric files (bottom) are plotted versus a time axis. Files identified by the observation time as part of one dataset are connected by a line. The name of the observed object is printed in red.

     


  • Editing the Tracklist

  • Afterwards "reducenight" will ask you, whether you want to edit the automatically created tracklist. If is is the first time you use this programme on the data you have to answer with y or yes. The routine then opens the file "tracklist.txt" with "nedit". Please change the corresponding line in the code when you prefer another editor. In the case that the directory contains an old tracklist, the user is asked, whether "reducenight" may overwrite it with a new one. For the above given example the tracklist contains the following informations:

    # track list for ./
    # nr.filesobjectdiameterphotfile A B
    02004-11-04T02:32:56.000+4HD1886032.86 ? ?
    12004-11-04T07:27:59.000+2HD37160 2.02 ? ?
    22004-11-04T08:52:10.000+2ZCMa -1.00? ?
    32004-11-04T09:14:44.000+2HD50778 3.76 ? ?

    When an object has been found in the calibrator database, the diameter is given, while for the science targets a "-1" indicates their status.

    Now the user has to identify the numbers of the two (photometry A & photometry B) photometric files belonging to the tracking data of the individual objects. This numbers can be found in the plot left of the squares indicating the files. If you are in doubt about the correct relations of the files, e.g. when the photometry has been repeated or an observation was cancelled, please try to clarify them with one of the other Tools. The example shown here is easy, because four different object have been observed without peculiarities:

    # track list for ./
    # nr.filesobjectdiameterphotfile A B
    02004-11-04T02:32:56.000+4HD1886032.86 0 1
    12004-11-04T07:27:59.000+2HD37160 2.02 2 3
    22004-11-04T08:52:10.000+2ZCMa -1.004 5
    32004-11-04T09:14:44.000+2HD50778 3.76 6 7

    To skip the reduction of a source, the user has to add a "#" at the beginning of the line.


  • Data Reduction

  • After saving the file the editor can be closed and the various objects are reduced interactively with "xmdv" as described in a previous section. The results are stored on disk. This archiving is initiated when the main window of MIA with the histograms and the fringe amplitudes is closed. Since the files with the suffix "sav" contain the informations handled before by the idl-object, every adjustment made in the main window is stored on disk too.

    If the programme finds in the directory previously saved results it asks the user, whether the reduction process should be skipped. If the user types n or no the reduction is redone. By hitting the <ENTER> key the old result is used. If the user wants to use an old result with, e.g. adjusted thresholds, the saved data can be inspected with MIA's graphical interface after a positive answer to the corresponding question. All adjustments made within the MIA window are again stored on disk. This allows a comparative inspection, adjustment, respectively, of all results.


  • Calibrating the Visibilities

  • Now the programme calibrates the raw visibilities of the science targets with the instrumental visibilities derived from the calibrators. The results of the individual science targets are stored in postscript files similar to that of the above example. The upper panel shows the individual calibrated visibilities. The colors distinguish between the calibrators (see below). The lower panel displays the mean and the error when averaging the results given in the upper panel.

    An overview of the calibrators and their corresponding colors are given in an additional file named "Cal.ps". Here the raw visibilities (dashed lines) and the instrumental visibilities (solid lines) derived after correcting the finite size of the calibrators are shown. In the here presented example one would improve the calibration of Z CMa by removing the erroneous calibrator HD 188603 by just inserting an "#" at the beginning of the corresponding line in the tracklist before repeating the calibration with the stored results.

    The described postscript files are located in the directory where the programme has been started. The data are stored in the files ending with "dat".