[Difx-users] Handling lin-pol data with difx2fits

[Leonid Petrov]

Dear Walter,

> It is true that the poltype is hard coded.  With some experimentation we 
> might be able to change that to X/Y as aspropriate.  At one point I 
> believe AIPS had trouble with other than R or L.  We can look into this 
> for DiFX 2.7.

  If AIPS at the moment has troubles with other than R and L, we can
ask Eric just to patch AIPS to treat X and Y or H and V as R and L on the flight
temporarily until better time come, if it is necessary. It should not take more
than 5 minutes. From the other hand, I got an impression that some folks 
already used AIPS for processing lin-pol data. Am I wrong? If yes, how did they 
do it?

  I have 6 lin-pol experiments on my table and a hundred or so to come within
weeks. We have to fix it now, i.e. today.

> As noted above, the FITS format is unable to describe such data, so this 
> is not possible.

  Although I heard a combinations of words "possible" and "not", I still cannot
grasp what do they mean together. We need amend FITS-IDI, I understand it.
So what? Even the US Constitution was amended, and more than once. Let us 
discuss how to do it. And we need fix difx2fits: today it tells that it does not 
like a combination of lin- and cir- data and stops. Yes, we already have the 
lin-cir and cir-lin data that need to be processed, and we plan to get more data 
like that. I already rolled my sleeves up and ready to do it. If you or anybody 
else can provide ideas and/or guidance, warn about pitfalls, contribute code, etc, 
I will appreciate it. But I cannot just do nothing and say: "these are the data that
I cannot process". Failure is not an option.

Sincerely,
Leonid
2019.04.11_15:38:06