[alma-config] New DOT and D resolution results

[Leonia Kogan]

HI Steven,

Thank you very much for your explanation. I have a comment to your 
following srarement:

>This is I believe as a consequence of the scaling factor issue which has
>been discussed earlier, explicitly shown by the extract below from the batch
>file used (recall that the scaling factor is pi (d squared) over 4 ln 2,
>where d is the number of pixels per synthesised beam in the original model
>image)

I figure out from the statement and from the input parameters you use for COMB,
that you compare the original model and the restored image given at different 
units: Jy/beam and Jy/pixel.

You use the coefficient 0.0353017 to bring the both images to the same unit.
Do you?

My comments:

1. This coefficient should be equal:

   pi/(4*ln(2)*(BEMJ*BEMN) / (RAINC*DECINC)

   where (BEMJ*BEMN) / (RAINC*DECINC) is the number of pixels 
      per synthesised beam.
   This number should not be squared as you told. You probaly meant that 
   d is the number of pixels in the one dimensional beam considering that 

   BEMJ = BEMN; RAINC = DECINC; and d = BEMJ/RAINC


   This coefficient should be different for different configuration if 
   the RA and DEL increaments are const but the beam size varies.


2. This coefficient can be a source of an error.
   I'd prefer to exclude it.

   In the simulation I used to carry out, I used the input model as 
   sum of CC component convolved with the given beam. UVCON used 
   the CC components as the model (CMODEL='COMP'). 
   COMB compared the IMAGR output (in JY/beam) with the CC components 
   convolved with the given beam (in JY/beam also). 
   So COMB used APARM=1,-1 calculating the actual 
   difference without an additional coefficient which can be a source of 
   an error.

   As I understand your original models are given as an image in Jy/pixel.
   You could convolve the image-model with the given beam and get 
   the convolved image in Jy/beam. The AIPS task CONVL (I think, hope) 
   carries out this job. 

   It is quite possible that this comment has been discussed already 
   and I missed it. Forget it at this case.


Leonia