[mmaimcal] Re: [Almasci] Two antennas

[Debra Shepherd]

Hi John, 

I'm looking through the offline requirements now - there are several that 
relate to the need to handle the polarized beam response in imaging but 
none (that I can find) specify that the offline package should be able to 
handle polarized beam patterns separately for each individual antenna.  The 
requirements relating to this are: 

Interferometric imaging section: 

OL 4.5-R1 Determination of and correction for pointing offsets and the 
polarized primary beam is critical to the ability to reliably mosaic using 
ALMA, and this must be available in the Package, preferable in several 
algorithmic forms.   Priority 1.

Mosaic imaging section: 

OL 5.2-R1 High-fidelity imaging of the entire primary beam in all Stokes 
parameters is the primary goal - therefore, incorporation of the polarized 
primary beam response of the array is required.  Priority 1.

OL 5.3-R2 Careful (polarized) primary beam correction and pointing 
correction is critical for high fidelity mosaic imaging and must be 
incorporated intot eh mosaicing algorithms.  Priority 1.


I do not find any text that says the beam patterns must be handled 
separately for each individual antenna.  Perhaps this was the intent but I 
was not part of the SSR when the requirements were written so I cannot say.  
Thus, it appears that it is appropriate to include the increased cost to 
develop the capability to handle individual polarized beam patterns.  

Debra


On Mon, 7 Nov 2005, John Richer wrote:

> 
> Dear Al,
> 
> Just a quick note on the article about impact of two antenna vendors on
> the Science IPT costs.  It is my understanding (and someone - maybe
> Robert Lucas or Christine Wilson - can correct me if I am wrong) that
> the software requirements we wrote down in the SSR several years ago
> already include the need to handle (polarised) beam patterns separately
> for each individual antenna.  I think it is categorised in the offline
> data processing requirements at the highest priority.  So I think this
> work has already been costed, and cannot be put in here again as an
> extra cost.  Whether such capabilites do yet exists within the offline
> or pipeline packages, I cannot say.
> 
> In addition, if there is any extra cost here, it is surely mainly
> against software rather than science?
> 
> Regards
> 
> John
> 
> 
> 

-- 
----
-------
-----------
Debra Shepherd				e-mail: dshepher at aoc.nrao.edu
National Radio Astronomy Observatory	phone:  (505) 835-7398
P.O. Box O				FAX:    (505) 835-7027
Socorro, NM 87801			http://www.nrao.edu/~dshepher