[daip] CCEDT and CALIB problems
Andy Biggs
abiggs at eso.org
Mon Aug 25 05:31:02 EDT 2008
Hi Amy. Thanks for your help. Personally, I still think that CCEDT
should output an empty CC table if no clean components 'make the grade'
so to speak; if that change could be made it would be a great help.
Thanks for clarifying what IMAGR does with regard to this.
However, I have another problem, this time with CALIB. I'm finding
solutions *in between* scans of the source that I'm calibrating with. I
have a multi-source file with alternate scans of my phase calibrator
(~3-min duration) and my target (~25 min duration). With solution
intervals of 2-3 min on my target things are fine. However, if the
solution interval goes to 4 min I then start seeing solutions *between*
scans. Not all scans are affected, just a couple usually, but the effect
is noticeable in SNPLT in two ways:
1) The gaps which are obvious between the other target scans are not visible
2) The solutions between the scans are obviously 'not right'
I've attached a postscript file that shows what I'm talking about. There
are 4 and a bit scans shown. Each scan receives 7 solutions, but between
two of the scans there are additional, discrepant, solutions. Looking at
the solutions using LISTR OPTY='GAIN' confirms that the solution
timestamp corresponds to the middle-ish of the phase-calibrator scan.
I seem to recall from a midnight job email recently that some work was
done on how CALIB decides on positions of solution intervals; maybe this
is related? Let me reiterate that everything is fine until I increase
the solution interval to 4 min. It might be significant that 4 min is
longer than the gaps between target scans (3.23 min).
I've also tried this on a file where I SPLATted the target source out of
the multi-source file i.e. there is only data from the target. I see the
same behaviour. Looking at the NX table, all scans have the same gap
between them so why only some would be affected I don't know. Here are
my inputs:
AIPS 2: CALIB: Task to determine calibration for data.
AIPS 2: Adverbs Values Comments
AIPS 2: ----------------------------------------------------------------
AIPS 2: Input uv data.
AIPS 2: INNAME 'TEST' UV file name (name)
AIPS 2: INCLASS 'SPLAT' UV file name (class)
AIPS 2: INSEQ 1 UV file name (seq. #)
AIPS 2: INDISK 1 UV file disk drive #
AIPS 2: Data selection (multisource):
AIPS 2: CALSOUR 'TEST' Calibrator sources
AIPS 2: *rest ' '
AIPS 2: QUAL -1 Calibrator qualifier -1=>all
AIPS 2: CALCODE ' ' Calibrator code ' '=>all
AIPS 2: SELBAND -1 Bandwidth to select (kHz)
AIPS 2: SELFREQ -1 Frequency to select (MHz)
AIPS 2: FREQID -1 Freq. ID to select.
AIPS 2: TIMERANG *all 0 Time range to use.
AIPS 2: BCHAN 1 Lowest channel number 0=>all
AIPS 2: ECHAN 7 Highest channel number
AIPS 2: ANTENNAS *all 0 Antennas to select. 0=all
AIPS 2: DOFIT *all 0 Subset of ANTENNAS list for
AIPS 2: which solns are desired.
AIPS 2: ANTUSE *all 0 Mean gain is calculated
AIPS 2: (CPARM(2)>0) using only the
AIPS 2: listed antennas. See explain.
AIPS 2: SUBARRAY 0 Subarray, 0=>all
AIPS 2: UVRANGE 0 0 Range of uv distance for full
AIPS 2: weight
AIPS 2: WTUV 0 Weight outside UVRANGE 0=0.
AIPS 2: WEIGHTIT 0 Modify data weights function
AIPS 2: Cal. info for input:
AIPS 2: DOCALIB 2 > 0 calibrate data & weights
AIPS 2: > 99 do NOT calibrate weights
AIPS 2: GAINUSE 5 CL table to apply.
AIPS 2: DOPOL -1 If >0 correct polarization.
AIPS 2: BLVER -1 BL table to apply.
AIPS 2: FLAGVER 0 Flag table version
AIPS 2: DOBAND -1 If >0 apply bandpass cal.
AIPS 2: Method used depends on value
AIPS 2: of DOBAND (see HELP file).
AIPS 2: BPVER -1 Bandpass table version
AIPS 2: SMOOTH *all 0 Smoothing function. See
AIPS 2: HELP SMOOTH for details.
AIPS 2:
AIPS 2: CLEAN map. See HELP.
AIPS 2: IN2NAME 'TEST' Cleaned map name (name)
AIPS 2: IN2CLASS 'ICL001' Cleaned map name (class)
AIPS 2: IN2SEQ 1 Cleaned map name (seq. #)
AIPS 2: IN2DISK 1 Cleaned map disk unit #
AIPS 2: INVERS 0 CC file version #.
AIPS 2: NCOMP *all 0 # comps to use for model.
AIPS 2: 1 value per field
AIPS 2: FLUX 0 Lowest CC component used.
AIPS 2: NMAPS 59 No. Clean map files
AIPS 2: CMETHOD ' ' Modeling method:
AIPS 2: 'DFT','GRID',' '
AIPS 2: CMODEL ' ' Model type: 'COMP','IMAG'
AIPS 2: SMODEL *all 0 Source model, 1=flux,2=x,3=y
AIPS 2: ** press RETURN for more, enter Q or next line to quit print **
AIPS 2: See HELP SMODEL for models.
AIPS 2:
AIPS 2: Output uv data file.
AIPS 2: OUTNAME ' ' UV file name (name)
AIPS 2: OUTCLASS ' ' UV file name (class)
AIPS 2: OUTSEQ 0 UV file name (seq. #)
AIPS 2: OUTDISK 1 UV file disk drive #
AIPS 2:
AIPS 2: Solution control adverbs:
AIPS 2: REFANT 10 Reference antenna
AIPS 2: SOLINT 4 Solution interval (min)
AIPS 2: SOLSUB 0 Solution subinterval
AIPS 2: SOLMIN 0 Min solution interval
AIPS 2: APARM *all 0 General parameters
AIPS 2: 1=min. no. antennas
AIPS 2: 2 > 0 => data divided
AIPS 2: 3 > 0 => avg. RR,LL
AIPS 2: 5 > 0 => avg. IFs.
AIPS 2: 6=print level, 1=good,
AIPS 2: 2 closure, 3 SNR
AIPS 2: 7=SNR cutoff (0=>5)
AIPS 2: 8=max. ant. # (no AN)
AIPS 2: 9 > 0 => pass failed soln
AIPS 2: 10 < 99 cal output weights
AIPS 2: Phase-amplitude Parameters:
AIPS 2: DOFLAG 0 Flag on closure error?
AIPS 2: SOLTYPE ' ' Soln type,' ','L1','GCON',
AIPS 2: 'R', 'L1R', 'GCOR'
AIPS 2: SOLMODE 'A&P' Soln. mode: 'A&P','P','P!A',
AIPS 2: 'GCON',
AIPS 2: SOLCON 0 Gain constraint factor.
AIPS 2: MINAMPER 0 Amplitude closure error
AIPS 2: regarded as excessive in %
AIPS 2: MINPHSER 0 Phase closure error regarded
AIPS 2: as excessive in degrees
AIPS 2: CPARM *all 0 Phase-amp. parameters
AIPS 2: 1 = Min el for gain
AIPS 2: normalization (deg)
AIPS 2: 2 >0 => normalize gain
AIPS 2: 3 avg. amp. closure err
AIPS 2: 4 avg. ph. closure err
AIPS 2: 5 >0 => scalar average
AIPS 2: 6 limit clipping in robust
AIPS 2: 7 limit display of closure
AIPS 2: errors
AIPS 2: SNVER 0 Output SN table, 0=>new table
AIPS 2: ANTWT *all 0 Ant. weights (0=>1.0)
AIPS 2: GAINERR *all 0 Std. Dev. of antenna gains.
AIPS 2: BADDISK *all 0 Disk no. not to use for
AIPS 2: scratch files.
Thanks,
Andy
--
Andy Biggs
ESO, ALMA Regional Centre
Karl-Schwarzschild-Strasse 2
D-85748 Garching, Germany
tel. +49-89-32006471
fax. +49-89-32006898
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