[daip] Question about the relation between DPFU and Poly in GC table

[Eric Greisen]

On 06/20/2019 02:38 AM, Cui Yuzhu wrote:
> Dear Eric,
> 
> Thanks for your support last time.
> 
> Now I came across another question when I check the GC table in AIPS.
> In APCAL task we need the Tsys information to calculate the SEFD.
> We have two parameters at the beginning of the Tsys: DPFU and poly.
> 
> I thought the the *‘real DPFU’ = DPFU×Poly. *But when I change the order 
> of these two parameters, I got different amplitude.
> It seems the relation is not simply multiplied. I attached one file to 
> show some results.
> Please have a look at it when you are available.
> 
> Could please offer some comments on this issue?
> Look forward to your reply.
> Thank you so much!
> 
> Best regards,
> Yuzhu
> 

I do not know much about the GC table.  Be careful in PRTAB to set 
NCOUNT to for example 10.  If it is 1 then PRTAB will only show one 
value.  However your NTERM_1 column seems to say that there is only 1.

The GC table is provided to AIPS by the telescope/correlator and AIPS 
can only show what is there.  If only one term is written in the 
FITS-IDI file then aips will only have one term.  I will ask your 
questions of people who may know more about this.

Eric Greisen