Examples

This is a wrapper for clean which includes automatic clean boxing.

Current capabilities include:

  1. Multi-frequency-continuum images or spectral channel imaging
  2. Stokes I imaging only
  3. Use starting mask
     
           vis -- Name of input visibility file
                   default: none; example: vis='ngc5921.ms'
           imagename -- Pre-name of output images:
                   default: none; example: imagename='m2'
                   output images are:
                     m2.image; cleaned and restored image
                            With or without primary beam correction
                     m2.psf; point-spread function (dirty beam)
                     m2.flux;  relative sky sensitivity over field
             m2.mask;  total clean regions
                     m2.model; image of clean components
                     m2.residual; image of residuals
           field -- Select fields in mosaic.  Use field id(s) or field name(s).
                      ['go listobs' to obtain the list id's or names]
                  default: ''= all fields
                  If field string is a non-negative integer, it is assumed to
                      be a field index otherwise, it is assumed to be a
              field name
                  field='0~2'; field ids 0,1,2
                  field='0,4,5~7'; field ids 0,4,5,6,7
                  field='3C286,3C295'; field named 3C286 and 3C295
                  field = '3,4C*'; field id 3, all names starting with 4C
           spw -- Select spectral window/channels
                  NOTE: This selects the data passed as the INPUT to mode
                  default: ''=all spectral windows and channels
                    spw='0~2,4'; spectral windows 0,1,2,4 (all channels)
                    spw='0:5~61'; spw 0, channels 5 to 61
                    spw='<2';   spectral windows less than 2 (i.e. 0,1)
                    spw='0,10,3:3~45'; spw 0,10 all channels, spw 3,
                       channels 3 to 45.
                     spw='0~2:2~6'; spw 0,1,2 with channels 2 through 6 in each.
                     spw='0:0~10;15~60'; spectral window 0 with channels
                        0-10,15-60
                     spw='0:0~10,1:20~30,2:1;2;3'; spw 0, channels 0-10,
                          spw 1, channels 20-30, and spw 2, channels, 1,2 and 3
           selectdata -- Other data selection parameters
                   default: True

      >>> selectdata=True expandable parameters
                   See help par.selectdata for more on these

                   timerange  -- Select data based on time range:
                       default: '' (all); examples,
                       timerange = 'YYYY/MM/DD/hh:mm:ss~YYYY/MM/DD/hh:mm:ss'
                       Note: if YYYY/MM/DD is missing date defaults to first
                 day in data set
                       timerange='09:14:0~09:54:0' picks 40 min on first day
                       timerange='25:00:00~27:30:00' picks 1 hr to 3 hr
                     30min on NEXT day
                       timerange='09:44:00' pick data within one integration
                         of time
                       timerange='>10:24:00' data after this time
                   uvrange -- Select data within uvrange (default units meters)
                       default: '' (all); example:
                       uvrange='0~1000klambda'; uvrange from 0-1000 kilo-lambda
                       uvrange='>4klambda';uvranges greater than 4 kilo lambda
                   antenna -- Select data based on antenna/baseline
                       default: '' (all)
                       If antenna string is a non-negative integer, it is
                assumed to be an antenna index, otherwise, it is
                considered an antenna name.
                       antenna='5&6'; baseline between antenna index 5 and
                      index 6.
                       antenna='VA05&VA06'; baseline between VLA antenna 5
                            and 6.
                       antenna='5&6;7&8'; baselines 5-6 and 7-8
                       antenna='5'; all baselines with antenna index 5
                       antenna='05'; all baselines with antenna number 05
                     (VLA old name)
                       antenna='5,6,9'; all baselines with antennas 5,6,9
                        index numbers
                  scan -- Scan number range.
                      default: '' (all)
                      example: scan='1~5'
                      Check 'go listobs' to insure the scan numbers are in
                 order.
           mode -- Frequency Specification:
                   NOTE: Channels deselected with spw parameter will contain all
                         zeros.
                   See examples below.
                   default: 'mfs'
                     mode = 'mfs' means produce one image from all
                   specified data.
                     mode = 'channel'; Use with nchan, start, width to specify
                             output image cube.  See examples below
                     mode = 'velocity', means channels are specified in
                   velocity.
                     mode = 'frequency', means channels are specified in
                   frequency.

      >>> mode expandable parameters (for modes other than 'mfs')
                   Start, width are given in units of channels, frequency
               or velocity as indicated by mode (note: only nearest neighbour
                      interpolation is available at this time).
                   nchan -- Number of channels (planes) in output image
                     default: 1; example: nchan=3
                   start -- Start input channel (relative-0)
                     default=0; example: start=5
                   width -- Output channel width in units of the input
                  channel width (>1 indicates channel averaging)
                     default=1; example: width=4
                   interpolation -- Interpolation type of spectral data when gridded on
                         the uv-plane
                     default = 'linear'
                   doconcat -- Tells autoclean to concatenate multiple channel images into
                         single image at the end of its run.  (Autoclean makes an image
                         for each channel, and cleans/boxes them one at a time.)
                     default = 'True'
               examples:
                   spw = '0,1'; mode = 'mfs'
                      will produce one image made from all channels in spw
                    0 and 1
                   spw='0:5~28^2'; mode = 'mfs'
                      will produce one image made with channels
                    (5,7,9,...,25,27)
                   spw = '0'; mode = 'channel': nchan=3; start=5; width=4
                      will produce an image with 3 output planes
                      plane 1 contains data from channels (5+6+7+8)
                      plane 2 contains data from channels (9+10+11+12)
                      plane 3 contains data from channels (13+14+15+16)
                   spw = '0:0~63^3'; mode='channel'; nchan=21; start = 0;
                width = 1
                      will produce an image with 20 output planes
                      Plane 1 contains data from channel 0
                      Plane 2 contains date from channel 2
                      Plane 21 contains data from channel 61
                   spw = '0:0~40^2'; mode = 'channel'; nchan = 3; start =
                5; width = 4
                      will produce an image with three output planes
                      plane 1 contains channels (5,7)
                      plane 2 contains channels (13,15)
                      plane 3 contains channels (21,23)

           psfmode -- method of PSF calculation to use during minor cycles:
                   default: 'clark': Options: 'clark','clarkstokes', 'hogbom'
                   'clark'  use smaller beam (faster, usually good enough);
                    for stokes images clean components peaks are searched in the I^2+Q^2+U^2+V^2 domain
                   'clarkstokes' locate clean components independently in each stokes image
                   'hogbom' full-width of image (slower, better for poor
                uv-coverage)
                   Note:  psfmode will be used to clean is imagermode = ''
           imagermode -- Advanced imaging e.g mosaic or Cotton-Schwab clean
                   default: imagermode='': Options: '', 'csclean'
                   default ''  => psfmode cleaning algorithm used

      >>> imagermode='csclean' expandable parameter(s):
                Image using the Cotton-Schwab algorithm in between major cycles
             cyclefactor -- Change the threshold at which
                   the deconvolution cycle will stop, degrid
                   and subtract from the visibilities.  For
                   poor PSFs, reconcile often (cyclefactor=4 or
                   5); For good PSFs, use cyclefactor 1.5 to
                   2.0. Note: threshold = cyclefactor * max
                   sidelobe * max residual.
                   default: 1.5; example: cyclefactor=4
             cyclespeedup -- Cycle threshold doubles in this
                   number of iterations default: -1;
                   example: cyclespeedup=3
                              try cyclespeedup = 50 to speed up cleaning
                 
           imsize -- Image pixel size (x,y).  DOES NOT HAVE TO BE A POWER OF 2
                   default = [256,256]; example: imsize=[350,350]
                   imsize = 500 is equivalent to [500,500]
                   Avoid odd-numbered imsize.
           cell -- Cell size (x,y)
                   default= '1.0arcsec';
                   example: cell=['0.5arcsec,'0.5arcsec'] or
                   cell=['1arcmin', '1arcmin']
                   cell = '1arcsec' is equivalent to ['1arcsec','1arcsec']
                   NOTE:cell = 2.0 => ['2arcsec', '2arcsec']
           phasecenter -- direction measure  or fieldid for the mosaic center
                   default: '' => first field selected ; example: phasecenter=6
                   or phasecenter='J2000 19h30m00 -40d00m00'
           restfreq -- Specify rest frequency to use for output image
                   default='' Occasionally it is necessary to set this (for
                   example some VLA spectral line data).  For example for
                   NH_3 (1,1) put restfreq='23.694496GHz'
           stokes -- Stokes parameters to image
                   default='I'; example: stokes='IQUV';
                   Options: 'I','IV''QU','IQUV','RR','LL','XX','YY','RRLL','XXYY'

           weighting -- Weighting to apply to visibilities:
                   default='natural'; example: weighting='uniform';
                   Options: 'natural','uniform','briggs',
                    'superuniform','briggsabs','radial'

      >>> Weighting expandable parameters
                   For weighting='briggs' and 'briggsabs'
                       robust -- Brigg's robustness parameter
                       default=0.0; example: robust=0.5;
                       Options: -2.0 to 2.0; -2 (uniform)/+2 (natural)
                   For weighting='briggsabs'
                       noise   -- noise parameter to use for Briggs "abs"
                weighting
                       example noise='1.0mJy'
                   npixels -- uv-cell area used for weight calculation
                       example npixels=1
                       Default = 0
                       superuniform:  0 Means 3x3 cells for weighting
                         the cell weight is proportional to the weight of
                         the 3x3 cells centered on it.
                       superuniform = F means 1x1 cell for averaging weights.
                       briggs/briggsabs: 0 is similar to 1x1 cell weight.
                         1 may? be similar to 3X3 cells.
                       Only npixels 0 or 1 recommended
                       
           mask -- Initial specification of cleanbox(es), mask image(s), and/or
            region(s) to be used for CLEANing.  For channel data (image cubes),
               any initial mask will be applied to every channel. mask default:
               [] (no masking); Possible specification types: (a) Explicit
            cleanbox pixel ranges example: mask=[110,110,150,145] clean
            region with blc=110,100; trc=150,145 (pixel values) (b)
            Filename with cleanbox pixel values with ascii format:
            example: mask='mycleanbox.txt' <fieldid blc-x blc-y
            trc-x trc-y> on each line
            1 45 66 123 124
            2 23 100 300 340
            (c) Filename for image mask example: mask='myimage.mask'
            (d) Filename for region specification (e.g. from viewer)
            example: mask='myregion.rgn' (e) Combinations of any of the
            above example: mask=[[110,110,150,145],'mycleanbox.txt',
            'myimage.mask','myregion.rgn']
               If include outlier fields, then mask need to be spefied in
               nested lists: e.g. mask=[[[110,110,150,145],'myimage.mask'],[],[20,20,40,40]]
               (A clean box with [110,110,150,145] and a image mask for main field,
                no mask for 1st outlier field, 1 clean box for second outlier field.)
           modelimage -- Name of model image(s) to initialize cleaning. If
                   multiple images, then these will be added together to
                   form initial starting model NOTE: these are in addition
                   to any initial model in the <imagename>.model image file
                   default: '' (none); example: modelimage='orion.model'
                   modelimage=['orion.model','sdorion.image'] Note: if the
                   units in the image are Jy/beam as in a single-dish
                   image, then it will be converted to Jy/pixel as in a
                   model image, using the restoring beam in the image
                   header
      >>> uvtaper=True expandable parameters
                   outertaper -- uv-taper on outer baselines in uv-plane
                     [bmaj, bmin, bpa] taper Gaussian scale in uv or
              angular units. NOTE: uv taper in (klambda) is roughly on-sky
                  FWHM(arcsec/200)
                     default: outertaper=[]; no outer taper applied
              example: outertaper=['5klambda']  circular taper
                     FWHM=5 kilo-lambda
                             outertaper=['5klambda','3klambda','45.0deg']
                             outertaper=['10arcsec'] on-sky FWHM 10"
                             outertaper=['300.0'] default units are meters
                         in aperture plane
                   innertaper -- uv-taper in center of uv-plane
                     [bmaj,bmin,bpa] Gaussian scale at which taper falls to
              zero at uv=0
                     default: innertaper=[]; no inner taper applied
                     NOT YET IMPLEMENTED                
           niter -- Maximum number iterations over all clean iterations.
                   default: 500;  example: niter=5000
           npercycle -- Number of clean minor cycles before making new clean region
            selection.
               default: 100;  example: npercycle = 100
           npercycle_speedup: If no new clean regions found during an iteration of
            clean region selections, increase npercycle by this factor.
               (Npercycle returns to initial value if new clean regions are later
                found.)
               default: 1.5;  example: npercycle_speedup = 2
           gain -- Loop gain for CLEANing
                   default: 0.1; example: gain=0.5
           pbcor -- Output primary beam-corrected image
               default: pbcor=False; output un-corrected image
               example: pbcor=True; output pb-corrected image (masked outside
                   minpb) Note: if you set pbcor=False, you can later
                   recover the pbcor image by dividing by the .flux image
                   (e.g. using immath)
           minpb -- Minimum PB level to use default=0.1;
                   The flux image is used to determine this
               except for the case of mosaic with ft='mosaic'
               where the flux.pbcoverage image is used.
                   example:
                   minpb=0.01 Note: this minpb is always in effect
                   (regardless of pbcor=True/False)
           clean_threshold -- Flux level at which to stop CLEANing
                   default: '0.0mJy';
                   example: threshold='2.3mJy'  (always include units)
                            threshold = '0.0023Jy'
                            threshold = '0.0023Jy/beam' (okay also)
           Nrms -- Stop cleaning when maximum residual is below this value times
            the current rms (outside the current clean regions).
               default: 6
               example: Nrms=4
           eps_maxres -- Convergence parameter to stop cleaning: stop if maximum
            residual has changed by less than a factor of eps_maxres.
               default: 0.01  (one per cent change)
               example: eps_maxres = 0.05
           allow_maxres_inc -- Parameter to stop cleaning: stop if maximum residual
            has increased between clean iterations this number of times.
               default: 3
               example: allow_maxres_inc = 2
           island_rms: threshold (this value times current rms) at which to box the
            residual image when searching for new clean regions
               default: 4
               example:  island_rms = 3
           diag: T/F switch to declare if pixels connected on the diagonal belong
            to the same island, when selecting pixels for clean boxing
               default: False
               example: diag = True
           peak_rms: threshold (this value times current rms) for peak pixel flux
            to qualify an island for clean boxing
               default: 6
               example: peak_rms = 5
           gain_threshold: threshold (this value times current maximum residual) of
            peak pixel in island to qualify island for clean boxing.
               default: 0.1
               example: gain_threshold = 0.5
           Npeak: maximum number of new clean regions to add each iteration
               default: 3
               example: Npeak = 5
           shape: parameter to determine shape of clean regions.
               0: all circles
               1: all boxes
               2: choose according to island shape (circles if island has similar
            dimension in x and y direction, box otherwise)
               default: 1  
               example: shape=2
           boxstretch: number of pixels to increase outward size of clean region,
            can range from -1 to 5.
               default: 1
               example: boxstretch = 3
           irregsize: for islands this large (dimension in pixels) or larger, fill
            in mask with island's actual shape rather than using a box or
            circle.  Set to 0 to ignore this parameter.
               default: 100
               example: irregsize = 50