[daip] GMRT data- UVFLP-BLOAT-DBCON
Eric Greisen
egreisen at nrao.edu
Mon May 19 13:40:30 EDT 2008
gcastell at iafe.uba.ar wrote:
> Dear all,
>
> I am working on GMRT data at 610 MHz, I am using the 31DEC08 version of AIPS.
>
> 1) I have two files of 128 channels, for the LSB and USB data.
>
> 2) I ran splat on the LSB data and also on the USB data. I obtained two
> new files of 7 channels.
> Concerning to SPLAT, I would like to know if the 31DEC08 version of AIPS
> has any problem (I read some emails about bugs in previous
> AIPS version).
> Below you can see the header for these files:
> I averaged 16 channels together, after selecting channels from 5 to 116 in
> each sideband
>
> **USB DATA**
> AIPS 1: Image=MULTI (UV) Filename=610_26_A_NEW.SPLAT . 1
> AIPS 1: Telescope=GMRT Receiver=GMRT
> AIPS 1: Observer=APR User #= 338
> AIPS 1: Observ. date=25-FEB-2008 Map date=08-MAY-2008
> AIPS 1: # visibilities 273196 Sort order TB
> AIPS 1: Rand axes: UU-L-SIN VV-L-SIN WW-L-SIN BASELINE TIME1
> AIPS 1: SOURCE
> AIPS 1: ----------------------------------------------------------------
> AIPS 1: Type Pixels Coord value at Pixel Coord incr Rotat
> AIPS 1: COMPLEX 3 1.0000000E+00 1.00 1.0000000E+00 0.00
> AIPS 1: STOKES 1 -1.0000000E+00 1.00 -1.0000000E+00 0.00
> AIPS 1: FREQ 7 6.1250000E+08 1.00 -2.0000000E+06 0.00
> AIPS 1: IF 1 1.0000000E+00 1.00 1.0000000E+00 0.00
> AIPS 1: RA 1 00 00 00.000 1.00 3600.000 0.00
> AIPS 1: DEC 1 00 00 00.000 1.00 3600.000 0.00
> AIPS 1: ----------------------------------------------------------------
>
> **LSB DATA*
>> imhe
> AIPS 1: Image=MULTI (UV) Filename=610_26_B_NEW.SPLAT . 1
> AIPS 1: Telescope=GMRT Receiver=GMRT
> AIPS 1: Observer=APR User #= 338
> AIPS 1: Observ. date=25-FEB-2008 Map date=09-MAY-2008
> AIPS 1: # visibilities 287112 Sort order TB
> AIPS 1: Rand axes: UU-L-SIN VV-L-SIN WW-L-SIN BASELINE TIME1
> AIPS 1: SOURCE
> AIPS 1: ----------------------------------------------------------------
> AIPS 1: Type Pixels Coord value at Pixel Coord incr Rotat
> AIPS 1: COMPLEX 3 1.0000000E+00 1.00 1.0000000E+00 0.00
> AIPS 1: STOKES 1 -1.0000000E+00 1.00 -1.0000000E+00 0.00
> AIPS 1: FREQ 7 6.1550000E+08 1.00 2.0000000E+06 0.00
> AIPS 1: IF 1 1.0000000E+00 1.00 1.0000000E+00 0.00
> AIPS 1: RA 1 00 00 00.000 1.00 3600.000 0.00
> AIPS 1: DEC 1 00 00 00.000 1.00 3600.000 0.00
> AIPS 1: ----------------------------------------------------------------
>
>
>
> 3) After SPLAT, I ran UVFLP on the LSB data to re-ordering the data. Then,
> I ran BLOAT, both on the output of UVFLP and on the output for SPLAT on
> the USB data.
>
> the inputs for BLOAT were:
>
> ** LSB DATA **
> 3723 BLOAT RELEASE ='31DEC08 ' /********* Start 13-MAY-2008 12:44:50
> 3724 BLOAT INNAME='G338_610_26B' INCLASS='UVFLP '
> 3725 BLOAT INSEQ= 1 INDISK= 1
> 3726 BLOAT OUTNAME='G338_610_26B' OUTCLASS='BLOAT '
> 3727 BLOAT OUTSEQ= 1 OUTDISK= 1
> 3728 BLOAT APARM(2) = 1 /1ST CHAN. NO. OF INPUT.
> 3729 BLOAT APARM(1) = 15 /NUMBER OF OUTPUT CHANNELS
> 3730 BLOAT APARM(3) = 1 / FIRST CHAN. COPIED.
> 3731 BLOAT APARM(3) = 7 / FIRST CHAN. COPIED.
> 3732 BLOAT /REFERENCE FREQ = 0.61550000E+09
>
> ** USB DATA**
> 2478 BLOAT RELEASE ='31DEC08 ' /********* Start 13-MAY-2008 12:48:36
> 2479 BLOAT INNAME='G338_610_26A' INCLASS='UVCOP '
> 2480 BLOAT INSEQ= 1 INDISK= 1
> 2481 BLOAT OUTNAME='G338_610_26A' OUTCLASS='BLOAT '
> 2482 BLOAT OUTSEQ= 1 OUTDISK= 1
> 2483 BLOAT APARM(2) = 9 /1ST CHAN. NO. OF INPUT.
> 2484 BLOAT APARM(1) = 15 /NUMBER OF OUTPUT CHANNELS
> 2485 BLOAT APARM(3) = 1 / FIRST CHAN. COPIED.
> 2486 BLOAT APARM(3) = 7 / FIRST CHAN. COPIED.
> 2487 BLOAT /REFERENCE FREQ = 0.61250000E+09
>
> 5) For DBCON I used the following inputs
> AIPS 1: INNAME 'G338_610_26B'
> AIPS 1: INCLASS 'BLOAT'
> AIPS 1: IN2NAME 'G338_610_26A'
> AIPS 1: IN2CLASS 'BLOAT'
> AIPS 1: REWEIGHT 0 0
> AIPS 1: DOPOS 1 1 If (1,1) true (+1) check pos.
> AIPS 1: 1 1 will shift second if nec.
> AIPS 1: 1 1 If (2,1) true check freq.
> AIPS 1: 1 0
> AIPS 1: DOARRAY -1 If true (+1) output data will
> AIPS 1: be the same subarray as input
> AIPS 1: Forced to +1 for multi-source
> AIPS 1: FQTOL -1 > 0 tolerance to not renumber
> AIPS 1: FQs of dataset 2 (in kHz)
>
> localh> DBCON1: Task DBCON (release of 31DEC08) begins
> localh> DBCON1: Scaling u,v,w of data set 2 by 1.0261224E+00
> localh> DBCON1: Scaling u,v,w of data set 1 by 1.0194963E+00
> localh> DBCON1: RA and DEC match to within 1 microarcsecond each
> localh> DBCON1: --I'm not going to shift positions
> localh> DBCON1: FREQUENCIES DIFFER BY TOO MUCH: 6.27500000E+08
> 6.28500000E+08
> localh> DBCON1: MULTI-FREQUENCY DATA BASES INCOMPATABLE
> localh> DBCON1: Purports to die of UNNATURAL causes
> localh> DBCON1: athos 31DEC08 TST: Cpu= 0.0 Real= 0
>
>
> I don't know what is wrong. Please, could you help me with my problem???
> I really need your comments!
>
Your choice of BCHAN etc in SPLAT has given you two data sets that do
not lie on the same frequency grid. As the message says, they are 1.e6
Hz different. The initial IMH show this. You will have to rethink the
SPLAT parameters if you wish to make this operation work.
Eric Greisen
More information about the Daip
mailing list