[daip] FLATN Help

[Julie Grant]

Hi,

I have been trying to run FLATN to mosaic my pointings together.  However, I
have come across some rather weird issues.

I have 80 pointings at 1.4 GHz.  Each one of my pointings have had FLATN run
on them as I used 61 facets to cover the primary beam for cleaning and
imaging.  I then  want to combine all 80 pointings into one mosaic.

My catalogue looks like this:

AIPS 1:    1 2619 AG768       .FLATN .    1 MA 17-MAY-2010 13:24:02
AIPS 1:    2 2619 AG768       .FLATN .    2 MA 17-MAY-2010 11:56:26
AIPS 1:    3 2619 AG768       .FLATN .    3 MA 17-MAY-2010 11:56:40
AIPS 1:    4 2619 AG768       .FLATN .    4 MA 17-MAY-2010 11:37:03
AIPS 1:    5 2619 AG768       .FLATN .    5 MA 17-MAY-2010 11:37:17
AIPS 1:    6 2619 AG768       .FLATN .    6 MA 17-MAY-2010 11:12:10
AIPS 1:    7 2619 AG768       .FLATN .    7 MA 17-MAY-2010 11:12:29
.....
AIPS 1:   80 2619 AG768       .FLATN .   80 MA 17-MAY-2010 11:12:29

I run FLATN using the following inputs:

AIPS 1: FLATN: Re-grid multiple fields and pointings to one image
AIPS 1: Adverbs     Values                 Comments
AIPS 1: ----------------------------------------------------------------
AIPS 1:                                    Input images
AIPS 1: INNAME     'AG768'                    Image name (name)
AIPS 1: INCLASS    'FLATN'                    Image name (class)
AIPS 1: INSEQ         1                       Image name (seq. #)
AIPS 1: INDISK       18                       Image disk drive #
AIPS 1: NFIELD        1                    Max number of fields per
AIPS 1:                                       pointing
AIPS 1: NMAPS         80                    Number of pointings
AIPS 1:                                    Output image
AIPS 1: OUTNAME    'AG768'                    Image name (name)
AIPS 1: OUTCLASS   ' '                        Image name (class)
AIPS 1: OUTSEQ        0                       Image name (seq. #)
AIPS 1: OUTDISK      18                       Image disk drive #
AIPS 1: IMSIZE     15000       15000       Output image size in pixels
AIPS 1: COORDINA     16          12        Central pixel coordinate
AIPS 1:               0          55        all 0 => use observed
AIPS 1:               0           0
AIPS 1: COOTYPE    ' '                     Desired projection type
AIPS 1: COOINC        0           0        Desired coordinate increment
AIPS 1: COOREF        0           0        Desired reference pixel
AIPS 1: ROTATE        0                    Rotation to be used (deg)
AIPS 1: REWEIGHT      0           0        (1) Interpolation halfwidth
AIPS 1:                                    (2) Minimum fraction of good
AIPS 1:                                        pixels required (0->1/3)
AIPS 1: WEIGHTIT      0                    Weight image down by WEIGHTIT
AIPS 1:                                    times radius from center in "
AIPS 1: EDGSKP       -1                    Skip pixels around the edges
AIPS 1:                                    inscribed ellipse also used
AIPS 1: OPTYPE     ' '                     For mosaics only (NMAPS>1)
AIPS 1:                                    compute and output expected
AIPS 1:                                    noise ('NOIS') or weight
AIPS 1:                                    ('WEIG').
AIPS 1: APARM      *all 0                  (1) >0 => do 3-D corr.
AIPS 1:                                       ONLY for snapshots
AIPS 1:                                    (2) Parallactic angle (deg)
AIPS 1:                                    (3) Zenith angle (deg)
AIPS 1:                                    (4-8) radial scaling parms
AIPS 1:                                    (9) Linear scaling
AIPS 1: PBPARM     *all 0                  Beam parameters (NMAPS > 1)
AIPS 1:                                    (1) Cutoff; (2) Use (3)-(7)
AIPS 1:                                    (3)-(7) Beam shape
AIPS 1: NOISE      *all 0                  Relative uncertainties by
AIPS 1:                                    pointing: 0 -> image header
AIPS 1: BADDISK    *all 0                  Disks to avoid for scratch

FLATN includes all 80 poinints however, some of the pointings have the
primary beam applied in a different way.  Either the pointing will have just
the bottom left corner of the pointing included in the mosaic or all the
pixels of the pointing will be blank.

I have checked that the field centre is correct, the size of the mosaic
covers the whole area, all pointings are in the 2000 cooridnate system.  I
have also made the imsize smaller and centred on the badly behaving pointing
and still, I get the same results.  Changing edskp =0 has the same results.


If I do not apply the primary beam correction, the field is included
correctly.

Is there something fundamental that I do not understand about FLATN (i.e.
missing something important) ?  Any help on this issue would be greatly
appreciated.  I am running 31DEC09 with the latest midnight job.

Thank in advance,
Julie
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