[daip] UVCON/FITS problem
Vincent Fish
vfish at haystack.mit.edu
Fri Oct 5 16:29:44 EDT 2007
I've attached five files:
1) A list of the inputs to UVCON
2) A FITS file on which it works. (Note that this was generated in
AIPS.)
3) A FITS file that doesn't work.
4) Another FITS file that doesn't work.
5) Still another FITS file that doesn't work, but this one only has
two axes (which, again, should theoretically be enough!).
Vincent
> Vincent Fish writes:
> > I'm having some problems running UVCON, and I was hoping you might have
> > some insights as to what's going wrong.
> >
> > The intent is to simulate a UV data set from an array, given an input
> > image and a few observational parameters. The task works, in that when
> > I use an image of Cyg A from Rick Perley and put in, for instance, the
> > VLBA (using AIPSTARS:VLBA_UVCON), I can generate a usable, realistic UV
> > data set.
> >
> > Now, what I'm trying to do is to use an image I've generated from
> > (somebody else's) theoretical modelling of a source. Their data were
> > in the form x,y,intensity; I've created a FITS file from this. When I
> > read it into AIPS, I can display the image properly on the TV (TVALL).
> > But when I try to use it as the input image in UVCON, it dies with the
> > following error messages:
> >
> > poisso> UVCON1: TABINI: REQUESTED CC FILE 0 DOES NOT EXIST
> > poisso> UVCON1: PROBLEM WITH CC FILE(ERROR= 2), WILL USE THE IMAGE
> > poisso> UVCON1: *** WARNING: OVERRIDING SPECIFIED COMPUTATION METHOD
> > poisso> UVCON1: IMAGE SIZES => DFT IS MUCH BETTER THAN GRIDDED
> > CONTINUING ANYWAY
> > poisso> UVCON1: SETGDS: imaging done with one OFFSET tangent plane
> > poisso> UVCON1: CHNDAT:COULD NOT FIND FREQ AXIS
> > poisso> UVCON1: FRQTAB: CHNDAT ERROR 1
>
> All of the messages up to the FREQ axis message make sense if you
> told it to use a CC model w/o providing one. You can tell it to use
> a CMODEL = 'IMAG' model and those messages will go away. I do not
> understand the next one which - as you have deduced is critical -
> since the UV header gets created early on, squirreled away and then
> sent in to the place where this test is done and the UV data header
> must have 5 axes including FREQ. At this stage, it appears that it is
> not testing your model header but the self-created UV header and it is
> failing. If you send me your model and your full set of adverbs, I
> suppose I could try it in the debugger (Leonia does not seem to be
> around just now).
>
> Eric Greisen
>
> >
> > Ah ha, you say. I've generated a 2-dimensional image that has no FREQ
> > axis, so of course UVCON (or CHNDAT, or AXEFND, or H2CHR) chokes. But
> > it's more fundamental than that. When I generate a 3-axis FITS file in
> > IDL (RA--SIN,DEC--SIN,FREQ) or a 4-axis one (...,STOKES), UVCON dies
> > with the same error message. This happens no matter whether I set the
> > FITS header keywords before FITLD'ing the images or afterward (using
> > PUTHEAD).
> >
> > Next, I tried FITLD'ing the 2-axis FITS file generated by IDL and using
> > the AIPS verb AXDEFINE to create a FREQ axis (explicitly called such).
> > It's clearly there. Here's the IMHEADER output (most of the keywords
> > are stolen from the Cyg A file):
> > AIPS 1: Image=Undefine (MA) Filename=05_200_2AXES.MODEL . 1
> > AIPS 1: Telescope=MWA-LFD Receiver=MWA-LFD
> > AIPS 1: Observer= User #= 101
> > AIPS 1: Observ. date=31-MAY-2002 Map date=05-OCT-2007
> > AIPS 1: Minimum= 0.00000000E+00 Maximum= 7.19929289E-04 JY/BEAM
> > AIPS 1: ----------------------------------------------------------------
> > AIPS 1: Type Pixels Coord value at Pixel Coord incr Rotat
> > AIPS 1: RA---SIN 128 10 26 36.288 1024.00 -0.020000 0.00
> > AIPS 1: DEC--SIN 128 26 00 00.000 1025.00 0.020000 0.00
> > AIPS 1: FREQ 1 2.0000000E+11 1.00 1.0000000E+00 0.00
> > AIPS 1: STOKES 1 1.0000000E+00 1.00 1.0000000E+00 0.00
> > AIPS 1: ----------------------------------------------------------------
> > AIPS 1: Coordinate equinox 2000.00
> > AIPS 1: Map type=NORMAL Number of iterations= 3000
> > AIPS 1: Conv size= 0.24522 X 0.23557 Position angle= 2.97
> > AIPS 1: Observed RA 10 26 36.300 DEC 26 00 00.00
> > AIPS 1: Maximum version number of extension files of type HI is 1
> > AIPS 1: Keyword = 'WTNOISE ' value = 1.000007E+00
> > AIPS 1: Keyword = 'CCFLUX ' value = 6.537626E+03
> > AIPS 1: Keyword = 'CCTOTAL ' value = 6.537626E+03
> > AIPS 1: Keyword = 'PARANGLE' value = -4.800507E+01
> > AIPS 1: Keyword = 'ZENANGLE' value = 9.515759E+01
> >
> > But yet again, UVCON/CHNDAT can't find the frequency axis. For the
> > record, I'm not sure why it even needs to. One specifies an observing
> > frequency via APARM(1), a bandwidth via APARM(8) (problem arises for
> > positive, negative, and zero values of APARM(8)), and a number of
> > frequency channels via APARM(9).
> >
> > What am I doing wrong? Inputs are below. (Yes, I know the VLBA doesn't
> > work at 200 GHz; etc.)
> >
> > Thanks for your help.
> > Vincent
> >
> > AIPS 1: UVCON Generates UV data for a given array and model
> > AIPS 1: Adverbs Values Comments
> > AIPS 1: ----------------------------------------------------------------
> > AIPS 1: INFILE 'AIPSTARS:VLBA_UVCON' Antenna location file name
> > AIPS 1: IN2FILE *all ' ' TSYS and Efficiency
> > AIPS 1: BLANK=>INFILE's data are used
> > AIPS 1: for TSYS and Efficiency
> > AIPS 1: OUTFILE *all ' ' Antenna location file name
> > AIPS 1: Positions are in equatorial
> > AIPS 1: coordinate system.
> > AIPS 1: IN2NAME '05_200_2AXES' Model image name (name)
> > AIPS 1: The both dimensions of the
> > AIPS 1: model must be 2**N pixels
> > AIPS 1: IN2CLASS 'MODEL' Model image name (class)
> > AIPS 1: IN2SEQ 1 Model image name (seq. #)
> > AIPS 1: IN2DISK 1 Model image disk unit #
> > AIPS 1: INVERS 0 CC file version #.
> > AIPS 1: OUTNAME ' ' Output UV file name (name)
> > AIPS 1: OUTCLASS ' ' Output UV file name (class)
> > AIPS 1: OUTSEQ 0 Output UV file name (seq. #)
> > AIPS 1: OUTDISK 0 Output UV file disk unit #.
> > AIPS 1: relatively of the initial
> > AIPS 1: declinat., given at APARM(3)
> > AIPS 1: per field (asec)
> > AIPS 1: APARM 200 0 Control information:
> > AIPS 1: -29 -12 1: Frequency of chan. 1, GHz
> > AIPS 1: 12 0 2: Wavelength of ch 1, cm
> > AIPS 1: 60 -8 IF both .LE. 0 then
> > AIPS 1: 0 0 wavelength = 0.1 cm
> > AIPS 1: 3: Source declination, deg
> > AIPS 1: 4: Min hour angle, hours
> > AIPS 1: 5: Max hour angle, hours
> > AIPS 1: The hour angles are for
> > AIPS 1: the given array center
> > AIPS 1: 6: Min antenna elevation, deg
> > AIPS 1: 7: Integration time, sec
> > AIPS 1: 0 => 1.D6
> > AIPS 1: to simmulate snapshot
> > AIPS 1: 8: Bandwidth(increment) of
> > AIPS 1: the freq. channel, MHz
> > AIPS 1: >=0 => it is increment to
> > AIPS 1: simulate multi chann. data
> > AIPS 1: =0 => Bandwidth = 1MHz
> > AIPS 1: <0 => one channel data to
> > AIPS 1: simulate multi frequency
> > AIPS 1: UV coverage
> > AIPS 1: 9: Number of freq. channels
> > AIPS 1: 0 => 1
> > AIPS 1: 10: Max blockage allowed
> > AIPS 1: 0 => 1 no blockage
> > AIPS 1: BPARM *all 0 Control information:
> > AIPS 1: 1: Multiplier of the calcul.
> > AIPS 1: noise. 0 => 1
> > AIPS 1: -1 => 0 (no noise)
> > AIPS 1: 2: Atmosphere noise at zenith
> > AIPS 1: in degrees.
> > AIPS 1: 3: RMS of pointing error,
> > AIPS 1: random among all antennas
> > AIPS 1: but constant in time,
> > AIPS 1: in arcsec
> > AIPS 1: If (BPARM(3).LT.0) then
> > AIPS 1:
> > AIPS 1: the phase and amplitude
> > AIPS 1: errors of each antenna
> > AIPS 1: are simulated instead
> > AIPS 1: of pointing error.
> > AIPS 1: ABS(BPARM(3)) is half
> > AIPS 1: range of homogeneously
> > AIPS 1: distributed phase, rad
> > AIPS 1:
> > AIPS 1: BPARM(4) is half
> > AIPS 1: range of homogeneously
> > AIPS 1: distributed natural LOG
> > AIPS 1: of factor to amplitude
> > AIPS 1:
> > AIPS 1: BPARM(5):
> > AIPS 1: 0 => only one (first)
> > AIPS 1: clean component is
> > AIPS 1: affected by the
> > AIPS 1: phase/amp noise
> > AIPS 1: 1 => all clean
> > AIPS 1: components are affected
> > AIPS 1:
> > AIPS 1: 4: global pointing error,
> > AIPS 1: constant in time for all
> > AIPS 1: antennas,
> > AIPS 1: in arcsec
> > AIPS 1: 5: RMS of pointing error,
> > AIPS 1: random among all antennas
> > AIPS 1: and in time,
> > AIPS 1: in arcsec
> > AIPS 1: 6: Type of the primary beam
> > AIPS 1: 1 => circular dish with
> > AIPS 1: the flat illumination
> > AIPS 1: 2 => illumination is 10dB
> > AIPS 1: down at the dish edge
> > AIPS 1: 3 => illumination is 15dB
> > AIPS 1: down at the dish edge
> > AIPS 1: The dish diameter is given
> > AIPS 1: at the INFILE (antenna 1)
> > AIPS 1: 4 => Gaussian beam with
> > AIPS 1: given BMAJ, BMIN, BPA
> > AIPS 1: in degrees
> > AIPS 1: 5 => Gaussian beam with
> > AIPS 1: variable BMAJ, BPA
> > AIPS 1: depending on the time
> > AIPS 1: .GT.0 =>Multiply the model
> > AIPS 1: by the primary beam.
> > AIPS 1: 0 => Not multiply the
> > AIPS 1: model by the primary beam.
> > AIPS 1: 7: Time tolerance, in minutes
> > AIPS 1: 0 => 1
> > AIPS 1: If the difference of the
> > AIPS 1: current and previous time
> > AIPS 1: is < the time tolerance,
> > AIPS 1: the pointing error or the
> > AIPS 1: phase of the antenna or
> > AIPS 1: primary beam parameters
> > AIPS 1: are not changed
> > AIPS 1: 8: Shift the UV data by
> > AIPS 1: RASHIFT, DECSHIFT?
> > AIPS 1: 0 => yes shift
> > AIPS 1: 1 => no shift
> > AIPS 1: 9: Range of the primary beam
> > AIPS 1: 0 => 2.5
> > AIPS 1: 10: If OUTFILE.NE.BLANK then
> > AIPS 1: 0 => calculate OUTFILE and
> > AIPS 1: exit
> > AIPS 1: 1 => calculate OUTFILE and
> > AIPS 1: carry out the rest of
> > AIPS 1: job
> > AIPS 1: BMAJ 0 FWHM major axis of the
> > AIPS 1: Gaussian primary beam, degree
> > AIPS 1: See help for the variable
> > AIPS 1: primary beam (BPARM(6)=5)
> > AIPS 1: BMIN 0 FWHM minor axis of the
> > AIPS 1: gaussian primary beam, degree
> > AIPS 1: BPA 0 Position angle of Gaussian
> > AIPS 1: primary beam, degree
> > AIPS 1: DO3DIMAG -1 1 => use W term calculating
> > AIPS 1: visibilities (only if
> > AIPS 1: CMETHOD='DFT', and
> > AIPS 1: CMODEL ='COMP')
> > AIPS 1: 0 => no W term calculating
> > AIPS 1: visibilities
>
> !DSPAM:47069c0f309398362916074!
>
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AIPS 1: UVCON Generates UV data for a given array and model
AIPS 1: Adverbs Values Comments
AIPS 1: ----------------------------------------------------------------
AIPS 1: INFILE 'AIPSTARS:VLBA_UVCON' Antenna location file name
AIPS 1: IN2FILE *all ' ' TSYS and Efficiency
AIPS 1: BLANK=>INFILE's data are used
AIPS 1: for TSYS and Efficiency
AIPS 1: OUTFILE *all ' ' Antenna location file name
AIPS 1: Positions are in equatorial
AIPS 1: coordinate system.
AIPS 1: IN2NAME '05_200_2AXES' Model image name (name)
AIPS 1: The both dimensions of the
AIPS 1: model must be 2**N pixels
AIPS 1: IN2CLASS 'MODEL' Model image name (class)
AIPS 1: IN2SEQ 1 Model image name (seq. #)
AIPS 1: IN2DISK 1 Model image disk unit #
AIPS 1: INVERS 0 CC file version #.
AIPS 1: OUTNAME ' ' Output UV file name (name)
AIPS 1: OUTCLASS ' ' Output UV file name (class)
AIPS 1: OUTSEQ 0 Output UV file name (seq. #)
AIPS 1: OUTDISK 0 Output UV file disk unit #.
AIPS 1: NMAPS 0 No. maps to use for model.
AIPS 1: BCOMP *all 0 First CLEAN comp to sub.
AIPS 1: 1 per field. 0 => 1
AIPS 1: NCOMP *all 0 Last CLEAN comp to sub.
AIPS 1: to use (0 => all)
AIPS 1: FLUX 0 Lowest CC component used.
AIPS 1: CMETHOD ' ' Modeling method:
AIPS 1: 'DFT','GRID'; ' '=>DFT
AIPS 1: CMODEL ' ' Model type: 'COMP','IMAG'
AIPS 1: ' ' => 'COMP'
AIPS 1: if clean components
AIPS 1: present
AIPS 1: else => 'IMAG'
AIPS 1: FACTOR 0 Factor times model fluxes.
AIPS 1: 0 => 1
AIPS 1: SMODEL *all 0 Source model, 1=flux,2=x,3=y
AIPS 1: See 'explain'.
AIPS 1: RASHIFT *all 0 Shift of the model center
AIPS 1: relatively of the initial
AIPS 1: RA=0, per field (asec)
AIPS 1: DECSHIFT *all 0 Shift of the model center
AIPS 1: relatively of the initial
AIPS 1: declinat., given at APARM(3)
AIPS 1: per field (asec)
AIPS 1: APARM 200 0 Control information:
AIPS 1: 26 -4 1: Frequency of chan. 1, GHz
AIPS 1: 4 0 2: Wavelength of ch 1, cm
AIPS 1: 60 -8 IF both .LE. 0 then
AIPS 1: 0 0 wavelength = 0.1 cm
AIPS 1: 3: Source declination, deg
AIPS 1: 4: Min hour angle, hours
AIPS 1: 5: Max hour angle, hours
AIPS 1: The hour angles are for
AIPS 1: the given array center
AIPS 1: 6: Min antenna elevation, deg
AIPS 1: 7: Integration time, sec
AIPS 1: 0 => 1.D6
AIPS 1: to simmulate snapshot
AIPS 1: 8: Bandwidth(increment) of
AIPS 1: the freq. channel, MHz
AIPS 1: >=0 => it is increment to
AIPS 1: simulate multi chann. data
AIPS 1: =0 => Bandwidth = 1MHz
AIPS 1: <0 => one channel data to
AIPS 1: simulate multi frequency
AIPS 1: UV coverage
AIPS 1: 9: Number of freq. channels
AIPS 1: 0 => 1
AIPS 1: 10: Max blockage allowed
AIPS 1: 0 => 1 no blockage
AIPS 1: BPARM *all 0 Control information:
AIPS 1: 1: Multiplier of the calcul.
AIPS 1: noise. 0 => 1
AIPS 1: -1 => 0 (no noise)
AIPS 1: 2: Atmosphere noise at zenith
AIPS 1: in degrees.
AIPS 1: 3: RMS of pointing error,
AIPS 1: random among all antennas
AIPS 1: but constant in time,
AIPS 1: in arcsec
AIPS 1: If (BPARM(3).LT.0) then
AIPS 1:
AIPS 1: the phase and amplitude
AIPS 1: errors of each antenna
AIPS 1: are simulated instead
AIPS 1: of pointing error.
AIPS 1: ABS(BPARM(3)) is half
AIPS 1: range of homogeneously
AIPS 1: distributed phase, rad
AIPS 1:
AIPS 1: BPARM(4) is half
AIPS 1: range of homogeneously
AIPS 1: distributed natural LOG
AIPS 1: of factor to amplitude
AIPS 1:
AIPS 1: BPARM(5):
AIPS 1: 0 => only one (first)
AIPS 1: clean component is
AIPS 1: affected by the
AIPS 1: phase/amp noise
AIPS 1: 1 => all clean
AIPS 1: components are affected
AIPS 1:
AIPS 1: 4: global pointing error,
AIPS 1: constant in time for all
AIPS 1: antennas,
AIPS 1: in arcsec
AIPS 1: 5: RMS of pointing error,
AIPS 1: random among all antennas
AIPS 1: and in time,
AIPS 1: in arcsec
AIPS 1: 6: Type of the primary beam
AIPS 1: 1 => circular dish with
AIPS 1: the flat illumination
AIPS 1: 2 => illumination is 10dB
AIPS 1: down at the dish edge
AIPS 1: 3 => illumination is 15dB
AIPS 1: down at the dish edge
AIPS 1: The dish diameter is given
AIPS 1: at the INFILE (antenna 1)
AIPS 1: 4 => Gaussian beam with
AIPS 1: given BMAJ, BMIN, BPA
AIPS 1: in degrees
AIPS 1: 5 => Gaussian beam with
AIPS 1: variable BMAJ, BPA
AIPS 1: depending on the time
AIPS 1: .GT.0 =>Multiply the model
AIPS 1: by the primary beam.
AIPS 1: 0 => Not multiply the
AIPS 1: model by the primary beam.
AIPS 1: 7: Time tolerance, in minutes
AIPS 1: 0 => 1
AIPS 1: If the difference of the
AIPS 1: current and previous time
AIPS 1: is < the time tolerance,
AIPS 1: the pointing error or the
AIPS 1: phase of the antenna or
AIPS 1: primary beam parameters
AIPS 1: are not changed
AIPS 1: 8: Shift the UV data by
AIPS 1: RASHIFT, DECSHIFT?
AIPS 1: 0 => yes shift
AIPS 1: 1 => no shift
AIPS 1: 9: Range of the primary beam
AIPS 1: 0 => 2.5
AIPS 1: 10: If OUTFILE.NE.BLANK then
AIPS 1: 0 => calculate OUTFILE and
AIPS 1: exit
AIPS 1: 1 => calculate OUTFILE and
AIPS 1: carry out the rest of
AIPS 1: job
AIPS 1: BMAJ 0 FWHM major axis of the
AIPS 1: Gaussian primary beam, degree
AIPS 1: See help for the variable
AIPS 1: primary beam (BPARM(6)=5)
AIPS 1: BMIN 0 FWHM minor axis of the
AIPS 1: gaussian primary beam, degree
AIPS 1: BPA 0 Position angle of Gaussian
AIPS 1: primary beam, degree
AIPS 1: DO3DIMAG -1 1 => use W term calculating
AIPS 1: visibilities (only if
AIPS 1: CMETHOD='DFT', and
AIPS 1: CMODEL ='COMP')
AIPS 1: 0 => no W term calculating
AIPS 1: visibilities
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