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UV_TRACKS

        [ASTRO\]UV_TRACKS   station1   station2  [station3  [...]]   [/FRAME
    [size]] [/HOUR_ANGLE Hmin [Hmax]] [/TABLE [Name]] [/HORIZON Elmin] [/IN-
    TEGRATION t] [/STATIONS ALL|list] [/WEIGHT Mode]

    Plot  interferometer  UV tracks as observed with the Plateau de Bure in-
    terferometer (but the command is in fact more general and  can  be  used
    with any array).

    Station  coordinates  are  searched  for  in the file defined by the AS-
    TRO_STATIONS logical variable. Stations  should  be  referred  to  by  a
    mnemonic (e.g. E03, W00 ...) given as arguments of UV_TRACKS.

    The  coordinates of the most recently selected SOURCE or PLANET are con-
    sidered. Option /HORIZON specifies a minimum elevation (in degrees)  for
    the  source. Option /HOUR_ANGLE can be used to limit the hour angle cov-
    erage. Default is from source rise  (above  the  minimum  elevation)  to
    source setup; Hmin and Hmax are in hours.  The frequency of the simulat-
    ed observation is read in the FREQUENCY SIC variable (which is also used
    by several other commands in ASTRO).

    UV_TRACKS  can be used iteratively, to simulate the observations of sev-
    eral configurations. Option /FRAME [size] should be used to start a  new
    UV  coverage. It clears the plot, draws the box, and open a new table if
    /TABLE is present. 'size' is the maximum UV spacing plotted,  in  meters
    (default  800  m).  Subsequent call to the command (without /FRAME) adds
    the new configurations. The user may select another color  pen  to  dis-
    tringuish  between the various coverages. A sketch of the interferometer
    described by ASTRO_STATIONS is also drawn, and the selected stations/an-
    tennas are highlighted.

    Option  /TABLE  can be used to write the sampling function (UV coverage)
    in a UV table for further processing such as producing beams  using  the
    task  UV_MAP.  Name  should  be specified only if option /FRAME has been
    used, to initialize the table. Subsequent call to the  UV_TRACK  command
    will  append the new observation to this table. The visibilities written
    in the UV table are constant, as if a point source were  observed  (real
    part  = 1, imaginary part = 0). The weight is by default constant, equal
    to 1. This can be modified using the /WEIGHT Mode option.  Mode  can  be
    UNIFORM (constant weight) or AIRMASS (weight proportional to airmass^-2,
    i.e. to sin(elevation)^2).

    Option /INTEGRATION t [min] is used to change the time interval  between
    points  in the UV plane (currently there is a max of 3000 points between
    HA_MIN and HA_MAX). Default is 15 minutes per point.

    ---- Notes for experts ----

    Option /STATIONS enable to access stations by their rank number  in  the
    ASTRO_STATIONS  file, rather by their mnemonic. ALL means 'take all sta-
    tions'. Switching between files describing interferometer  stations  can
    be  done  inside ASTRO by redefining the ASTRO_STATIONS logical variable
    using the command
    SIC LOG ASTRO_STATIONS "path/to/the/desired/file"
    The BURE stations are described in the file ephemeris/astro_stations.dat
    (and accessed by default on most ASTRO installs, or otherwise by
    SIC LOG ASTRO_STATIONS GAG_ASTRO_DATA:astro_stations.dat)



Gildas manager 2011-04-01