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Basic Information on uvplanet


Task: uvplanet
Purpose: Fiddle planetary and solar system data.
Categories: uv analysis

        uvplanet is a Miriad task used to fiddle visibility datasets
        from planetary (and other solar system) observations. It can:
          - Add planet orientation parameters (plmaj,plmin,plangle) to
            the dataset. uvplanet recognises planets by their source name,
            and knows their orientations as a function of time.
          - Apply a time-varying phase shift to track the object.
          - Subtract a thermal disk.
          - Subtract background sources, accounting for a moving phase centre.
 

Key: vis
        The name of the input uv datasets. Several can be given
        Wildcards are supported. No default.

Key: out
        The name of the output uv data-set. There is no default name.

Key: select
        The normal uv selection commands. The default is to select everything.

Key: pltb
        Parameters for planets only, which determine model for the planetary
        disk to be subtracted off. It consists of one or two values. The
        first is the blackbody temperature of the disk, in Kelvin.
        The second is the limb darkening parameter. The limb darkening
        parameter is a value between 0 and 1. The apparent brightness of
        the disk falls off as cos(theta)**limb.
        uvplanet has built-in ephemerides and models of the planets which
        gives their apparent sizes and shapes.
        The default is 0 for both parameters (i.e. do not subtract off a disk).

Key: options
        This gives extra processing options. Several options can be given,
        each separated by commas. They may be abbreviated to the minimum
        needed to avoid ambiguity. Possible options are:
           replace     Replace the data with the blackbody disk and point
                       sources (the normal behaviour is to subtract the
                       blackbody disk and point sources).
           pparam      Normally uvplanet uses its own ephemerides to determine
                       planet major and minor axes and position angle to model
                       the planets disk. The pparam option causes uvplanet to use
 
           magnetic    For Jupiter only: The magnetic axis is used to
                       set planet orientation parameters. This overrides the
                       normal behaviour of using the spin axis.
           arcane      The format for the pmotion text files is the
                       "arcane" format (see below).
        The following options can be used to turn off calibration corrections.
        The default is to apply any calibration present.
           nocal       Do not apply the gains table.
           nopass      Do not apply bandpass corrections.
           nopol       Do not apply polarization corrections.

Key: sources
        This gives the position and flux of point sources to be subtracted
        from the visibility dataset. Many sources can be given. Each
        source is specified by three numbers:
          ra dec flux
        The RA and DEC are in normal Miriad format, and the flux is in Jy.

Key: pmotion
        This parameter allows phase shifts to be applied to the data to
        make the phase centre track the object of interest. Assuming that
        the object has significant proper motion, this can
        correct for phase tracking errors (e.g. wrong ephemeris) or perhaps
        no tracking at all. One or two tracking files can be given. The first
        file gives the centre of the object (as a function of time). The second
        gives the phase centre of the observation (as a function of time).
        If both files are given, the data are phase shifted to the centre
        of the object (i.e. corrects for tracking errors). If only one file
        is given, then the RA and DEC in the dataset are taken as the
        phase centre of the telescope.
 
        The "pmotion" parameter can also be used to correct the RA and DEC
        stored in the dataset. If these are incorrect (e.g. many telescopes
        and the FITS format, do not store the time-varying RA/DEC, even though
        they track time varying RA/DEC), then giving the one text file
        twice will cause the RA and DEC to be corrected and no shifts being
        applied.
 
        The text files contain potentially many lines, with each line
        giving a sky position at a given time.
        Two formats for the text files are possible (if there are
        two input files, both must be in the same format). The normal format
        consists of 3 values per line, being
 
          time ra dec
 
        with "time" (UTC), "ra" and "dec" being the position of the object at
        a given time. The time, ra and dec are in the normal Miriad formats.
        The times should be in increasing order. Linear interpolation
        is used to estimate positions between the given times.
 
        A convenient way to develop this file is through the JPL ``Horizons''
        service. This is accessed through
 
          telnet ssd.jpl.nasa.gov 6775
 
        Using a text reformating tool (e.g. PERL), the output from Horizons
        is readily converted to the format required by uvplanet.
        Documentation on the Horizons system is available from
 
          http://ssd.jpl.nasa.gov/horizons.html
 
        The other possible format is the ``arcane'' format, which will be
        expected if "options=arcane" is given. This format is provided for
        obscure historical support. It consists of 6 values per line, being
 
          start_time time ra dec dra ddec
 
        The times are in modifed Julian days, ra and dec are in turns,
        and the rate parameters, "dra" and "ddec", are in turns/day. The
        record is considered valid after "start_time", and the rates
        are used to estimate positions between given times.

Generated by miriad@atnf.csiro.au on 21 Jun 2016