[daip] IMAGR

[Nectaria Gizani]

     Thank you very much for the explanations. Yes I did mean to include
the whole field, but I better check again.

Nectaria

On Thu, 9 Jun 2005, Eric Greisen wrote:

> Nectaria Gizani writes:
>  > 	Hi, 
>  > 
>  > I was running Imagr on a very faint source, EVN data. I have boxed the
>  > real emission and carried on cleaning. When the new residual map came up,
>  > with the source "gone", I have put boxes on what I thought was also real
>  > emission and I turned off the tv. When imagr finished after 5000
>  > iterations, and I saw the map, it looked fine to me, with a low
>  > noise. However I had a look at the message window. It was then that I saw
>  > that somewhere in the 300 iteration, imagr reported "something is going
>  > wrong, abandon clean". However it carried on for the rest of the
>  > iterations ending succesfully, instead of dying!! I include the message in
>  > what follows. Is there something to worry about?
> 
>    Perhaps there is something to worry about.  Before you turned off
> the TV you changed the "BOX" to include all of the image including
> edge pixels that are always affected by imaging defects.  I include
> some of the relevant messages:
>  > IMAGR2 10:44:17 Field   1 min = -906.8 MicroJy,max =  998.0 MicroJy
>  > IMAGR2 10:44:17 CLNTEL: TELL operation code CHAN received
>  > IMAGR2 10:44:17 Loading field   1 to TV from -1.289E-03 to  3.015E-03
>  > IMAGR2 11:08:10 TVDBOX: BOX( 1) =   248.00  249.00  253.00  254.00
>  > IMAGR2 11:08:10 TVDBOX: BOX( 2) =   259.00  249.00  265.00  252.00
>  > IMAGR2 11:08:10 TVDBOX: BOX( 3) =   264.00  251.00  268.00  256.00
>  > IMAGR2 11:08:10 TVDBOX: BOX( 4) =   246.00  271.00  249.00  274.00
>  > IMAGR2 11:08:12 Clean continuing
>  > IMAGR2 11:08:12 BGC Clean: using 1019 cell beam + residuals >    73.21
>  > MicroJy
>  > IMAGR2 11:08:12      110 Residual map points loaded
>  > IMAGR2 11:08:12 Reached minimum allowed flux   =  320.505 MicroJy iter=
>  > 104
>  > IMAGR2 11:08:12 Total Cleaned flux density     =    7.892 MilliJy      104
>  > comps
>  > IMAGR2 11:08:12 VISDFT: Begin DFT component subtraction
>  > IMAGR2 11:08:12 I Polarization model processed
>  > IMAGR2 11:08:13 Field   1 min = -778.9 MicroJy,max =  773.9 MicroJy
>  > IMAGR2 11:08:13 Loading field   1 to TV from -1.289E-03 to  3.015E-03
>  > IMAGR2 11:08:27 TVDBOX: BOX( 1) =     2.00    1.00  512.00  512.00
>  > IMAGR2 11:08:30 Turning off DOTV option - use TELL to turn on
>  > IMAGR2 11:08:30 BGC Clean: using   15 cell beam + residuals >   293.17
>  > MicroJy
>  > IMAGR2 11:08:30    19984 Residual map points loaded
>  > IMAGR2 11:08:30 SOMETHING IS GOING WRONG - ABANDON CLEAN
>  > IMAGR2 11:08:30 Reached minimum algorithm flux = -577.870 MicroJy iter=
>  > 205
>  > IMAGR2 11:08:30 Total Cleaned flux density     =    6.302 MilliJy      205
>  > comps
> 
> Note the TVDBOX message above.  Then 20000 pixels get cleaned in the
> minor cycle rather than 100 or so.  The net Clean flux dropped a lot
> which is what caused the ABANDON message.  Did you mean to Clean the
> full area?
> 
> If so it is probably okay = otherwise you might want to repeat
> things.
> 
> Eric Greisen
>