[daip] IMAGR with multi facets
Eva Schinnerer
schinner at mpia-hd.mpg.de
Sun Jun 8 08:45:37 EDT 2008
Hi Eric,
I don't know if Gaelle has already replied.
It turns out that using the old AIPS version was causing the strange
pattern to occur. Gaelle is now using the latest AIPS release and
everything works fine. I was under the assumption that our machine had
always the latest version of AIPS installed which is apparently not
the case.
Thank you for looking into this.
Best wishes,
eva
On Jun 6, 2008, at 6:06 PM, Eric Greisen wrote:
> Gaelle Dumas wrote:
>> Dear Dr. Greisen,
>> I am doing images of VLA data of M51 at 3.6 (B+C), 6 (B+C+D) and
>> 20cm (A+B+C+D), using multiple fields.
>> There is no error or warning messages during the cleaning process,
>> however the final maps for the 3.6 and 6cm data have got very bad
>> stripped features (see the joint ps file, corresponding to the
>> 3.6cm data, north pointing, combination of all the facets)
>> I checked carefully the calibration steps, and I didn't find any
>> problem
>> Here is what I did for the 3.6cm, North pointing, to create the
>> clean map:
>> I run setfc on the uv file with the inputs:
>> AIPS 1: SETFC: Task to make a BOXFILE for input to IMAGR
>> AIPS 1: Adverbs Values Comments
>> AIPS 1:
>> ----------------------------------------------------------------
>> AIPS 1: INNAME 'M51_N_4CM_CD' UV dataset name (name)
>> AIPS 1: INCLASS 'IF 1+2' UV
>> dataset name (class)
>> AIPS 1: INSEQ 1 UV dataset name (seq. #)
>> AIPS 1: INDISK 1 Disk drive #
>> AIPS 1: SOURCES *all ' ' Source selected
>> AIPS 1: BCOUNT 1 First field number to use
>> AIPS 1: BOXFILE 'WORK:BOX_XBAND_N'
>> AIPS 1: disk file to write to (the
>> AIPS 1: input BOXFILE for IMAGR)
>> AIPS 1: CELLSIZE 0.4 0.4 (X,Y) size of grid in asec
>> AIPS 1: IMSIZE 4096 4096 field size
>> AIPS 1: SHIFT 0 0 Position shift (RA,Dec)
>> asec
>> AIPS 1: for all fields
>> AIPS 1: FLUX 2.500E-05 Minimum component flux =
>> AIPS 1: (source * beam)
>> AIPS 1: BPARM 0.5 5 (1) Inner region radius
>> (deg)
>> AIPS 1: *rest 0 (2) Field overlap (pixels)
>> AIPS 1: (3) Factor to scale NVSS
>> AIPS 1: fluxes, 0 -> 1
>> AIPS 1: (4) Radius NVSS search
>> (deg)
>> AIPS 1: (5) Flux limit in NVSS
>> (Jy)
>> AIPS 1: (6) IMSIZE for NVSS fields
>> AIPS 1: (7) IMSIZE for Sun fields
>> AIPS 1: (8) Write Clean boxes for
>> AIPS 1: NVSS fields
>> AIPS 1: (9) Maximum allowed phase
>> AIPS 1: error in imaging
>> AIPS 1: (10) Points per beaam
>> AIPS 1: PBPARM *all 0 Beam parameters:
>> AIPS 1: (1) Cutoff; (2) Use (3)-
>> (7)
>> AIPS 1: (3)-(7) Beam shape parms
>> AIPS 1: INFILE ' '
>> AIPS 1: NVSS input file name
>> AIPS 1: ' ' => AIPS provided.
>> this defined 7 facets
>> then I run imagr with the following inputs
>> AIPS 1: IMAGR: Wide field imaging/Clean task
>> AIPS 1: Adverbs Values Comments
>> AIPS 1:
>> ----------------------------------------------------------------
>> AIPS 1: INNAME 'M51_N_4CM_CD' Input UV data (name)
>> AIPS 1: INCLASS 'IF 1+2' Input UV data (class)
>> AIPS 1: INSEQ 1 Input UV data (seq. #)
>> AIPS 1: INDISK 1 Input UV data disk drive #
>> AIPS 1: SOURCES *all ' ' Source name
>> AIPS 1: QUAL -1 Calibrator qualifier
>> -1=>all
>> AIPS 1: CALCODE ' ' Calibrator code '
>> '=>all
>> AIPS 1: TIMERANG *all 0 Time range to use
>> AIPS 1: SELBAND -1 Bandwidth to select (kHz)
>> AIPS 1: SELFREQ -1 Frequency to select (MHz)
>> AIPS 1: FREQID -1 Freq. ID to select.
>> AIPS 1: SUBARRAY 0 Sub-array, 0=>all
>> AIPS 1: DOCALIB -1 If >0 calibrate data
>> AIPS 1: = 2 calibrate weights
>> AIPS 1: GAINUSE 0 CL (or SN) table to apply
>> AIPS 1: DOPOL -1 If >0.5 correct
>> polarization.
>> AIPS 1: BLVER -1 BL table to apply.
>> AIPS 1: FLAGVER 0 Flag table version
>> AIPS 1: DOBAND -1 If >0.5 apply bandpass
>> cal.
>> AIPS 1: Method used depends on
>> value
>> AIPS 1: of DOBAND (see HELP file).
>> AIPS 1: BPVER -1 Bandpass table version
>> AIPS 1: SMOOTH *all 0 Smoothing function. See
>> AIPS 1: HELP SMOOTH for details.
>> AIPS 1: STOKES ' ' Stokes parameters (see
>> HELP)
>> AIPS 1: BCHAN 1 Low freq. channel 0 for
>> cont.
>> AIPS 1: ECHAN 0 Highest freq channel
>> AIPS 1: CHANNEL 0 Restart channel number
>> AIPS 1: NCHAV 1 Number of chan. to
>> average.
>> AIPS 1: CHINC 1 Channel incr. between
>> maps.
>> AIPS 1: BIF 0 First IF in average.
>> AIPS 1: EIF 0 Last IF in average.
>> AIPS 1: OUTNAME ' ' Output image name (name)
>> AIPS 1: OUTDISK 1 Output image disk drive #
>> AIPS 1: OUTSEQ 0 Output seq. no.
>> AIPS 1: OUTVER 0 CC ver. no (Continuum
>> only)
>> AIPS 1: *** SET OUTVER ON RESTARTS
>> AIPS 1: IN2NAME ' ' UV work file name
>> AIPS 1: IN2CLASS ' ' UV work file class
>> AIPS 1: IN2SEQ 0 UV work file seq
>> AIPS 1: *** SET TO KEEP WORK FILE
>> AIPS 1: IN2DISK 0 UV work file disk
>> AIPS 1: CELLSIZE 0.4 0.4 (X,Y) size of grid in asec
>> AIPS 1: IMSIZE 4096 4096 Minimum image size
>> AIPS 1: NFIELD 7 Number of fields (max
>> 4096)
>> AIPS 1: DO3DIMAG 1 > 0 => use different
>> tangent
>> AIPS 1: points for each field
>> AIPS 1: FLDSIZE *all 0 Clean size of each field.
>> AIPS 1: RASHIFT *all 0 RA shift per field (asec)
>> AIPS 1: DECSHIFT *all 0 DEC shift per field (asec)
>> AIPS 1: UVTAPER 0 0 (U,V) Gaussian taper
>> AIPS 1: units are kilo-lambda
>> AIPS 1: UVRANGE 0 0 Min & max baseline
>> (klambda)
>> AIPS 1: GUARD 0 0 x,y guard band fractional
>> AIPS 1: radius
>> AIPS 1: ROTATE 0 Rotate image CCW from N by
>> AIPS 1: ROTATE degrees
>> AIPS 1: ZEROSP 1 0 0-spacing fluxes and
>> weights
>> AIPS 1: 0 0 SEE HELP!!
>> AIPS 1: 5
>> AIPS 1: UVWTFN ' ' UV dist. weight function
>> AIPS 1: UVSIZE 0 0 Array size for doing
>> uniform
>> AIPS 1: weights. 0 -> actual
>> field
>> AIPS 1: size.
>> AIPS 1: ROBUST 0 Robustness power: -5 ->
>> pure
>> AIPS 1: uniform weights, 5 =>
>> natural
>> AIPS 1: UVBOX 0 Additional rows and
>> columns
>> AIPS 1: used in weighting.
>> AIPS 1: UVBXFN 1 Box function type when
>> UVBOX
>> AIPS 1: > 0. 0 -> 1 round pill
>> box.
>> AIPS 1: XTYPE 5 Conv. function type in x
>> AIPS 1: default spheroidal
>> AIPS 1: YTYPE 5 Conv. function type in y
>> AIPS 1: default spheroidal
>> AIPS 1: XPARM *all 0 Conv. function parms for x
>> AIPS 1: YPARM *all 0 Conv. function parms for y
>> AIPS 1: NITER 50000 Maximum # of Clean
>> components
>> AIPS 1: BCOMP *all 0 Begin at BCOMP component
>> AIPS 1: Specify for each field.
>> AIPS 1: ALLOKAY 0 For restart: > 0 => beams
>> AIPS 1: okay, > 1 => work file too
>> AIPS 1: NBOXES 0 Number of boxes for Clean
>> AIPS 1: NB: field 1 only.
>> AIPS 1: CLBOX *all 0 Four coordinates for
>> each box
>> AIPS 1: BOXFILE 'WORK:BOX_XBAND_N' Input file of field params
>> AIPS 1: and Clean boxes; ' ' =>
>> use
>> AIPS 1: FLDSIZE, RASHIFT,
>> DECSHIFT,
>> AIPS 1: NBOXES, CLBOX only.
>> AIPS 1: OBOXFILE 'WORK:BOX_XBAND_N_CLEAN'Output file for final
>> Clean
>> AIPS 1: boxes
>> AIPS 1: GAIN 0.1 Clean loop gain
>> AIPS 1: FLUX 2.500E-05 Minimum Clean component
>> (Jy)
>> AIPS 1: MINPATCH 121 Min. BEAM half-width in
>> AP.
>> AIPS 1: BMAJ 0 FWHM(asec) major axis
>> Clean
>> AIPS 1: restoring beam.
>> AIPS 1: BMIN 0 FWHM(asec) minor axis
>> Clean
>> AIPS 1: restoring beam.
>> AIPS 1: BPA 0 Clean beam position angle
>> AIPS 1: OVERLAP 2 1 => restore components to
>> AIPS 1: overlapped fields, >=2=>
>> AIPS 1: expect overlaps in
>> Cleaning
>> AIPS 1: PHAT 0 Prussian hat height.
>> AIPS 1: FACTOR 0 Speedup factor see HELP
>> AIPS 1: CMETHOD ' ' Modeling method:
>> AIPS 1: 'DFT','GRID',' '
>> AIPS 1: IMAGRPRM *all 0 Task enrichment parameters
>> AIPS 1: (1) Antenna diameter (m)
>> AIPS 1: (2) Source Spectral index
>> AIPS 1: (3) Frequency scaling
>> factor
>> AIPS 1: (4) > 0 -> SDI Clean
>> factor
>> AIPS 1: (5) >0 => scale residuals
>> AIPS 1: (6) Half-width in x of box
>> AIPS 1: (7) Half-width in y of box
>> AIPS 1: (8) Filter components
>> whose
>> AIPS 1: neighborhood is weaker
>> than
>> AIPS 1: IMAGRPRM(8) Jy. 0 ->
>> don't
>> AIPS 1: (9) Radius in pixels for
>> the
>> AIPS 1: IMAGRPRM(8) test.
>> AIPS 1: (10) multiplier of image
>> size
>> AIPS 1: to get beam size: 0 => 2;
>> AIPS 1: 2, 1, 0.5 0.25 supported
>> AIPS 1: (11-16) Multi-resolution
>> AIPS 1: added controls
>> AIPS 1: (19) Dynamic range limit
>> AIPS 1: (20) Retry factor (see
>> help)
>> AIPS 1: NGAUSS 0 Number of resolutions to
>> use
>> AIPS 1: WGAUSS *all 0 Resolutions in arc sec
>> >= 0
>> AIPS 1: FGAUSS *all 0 Minimum flux for each
>> resol.
>> AIPS 1: MAXPIXEL 70000 Maximum pixels searched in
>> AIPS 1: each major cycle.
>> AIPS 1: DOTV 1 Display residuals on TV ?
>> AIPS 1: Start with field = DOTV
>> AIPS 1: BADDISK *all 0 Disks to avoid for
>> scratch.
>> as I said above, there is no error or warning message from imagr
>> during the cleaning process.
>> The stripes appear and become more and more important while the
>> cleaning is done.
>> (there is no stripe when I use a single field, with normale and MR
>> clean process)
>> There is however a message I don't clearly understand and that
>> comes regularly during the cleaning process:
>> ALGSTB: Only 635 rows in AP (need 771)
>> I increased the values of MINPATCH and MAXPIXELS after having this
>> message with the default values, but this message is still here.
>> I am using aips version 31DEC05.
>> Could you tell me what inputs I should change to get rid of these
>> stripes?
>> Or do you think it is due to bad data reduction?
>> Also, should I try on a more recent version of aips?
>> many thanks in advance
>> Gaelle
>
> I don't know how I can help with just this information. There is
> nothing in the imaging process which should cause stripes to appear.
> I do wonder if 4096x4096 images are correct for your data. (I
> usually run SETFC once with IMSIZE and CELLSIZE 0 to find out the
> image and cell sizes I should use.) I would recommend using a more
> modern version of AIPS - if there is actually a bug the oldest
> version I will fix is 31DEC07 at this point. The ALGSTB message
> will go away in modern versions which adapt the "AP" size to the
> size of the problems. Do the stripes start out in a non-central
> facet? I don't immediately see anything that should cause trouble.
>
> Eric Greisen
>
>
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