PGFLAG on UVCATed uv files

[and460]

Hi guys,

I have observations of the same object taken in two different array configurations. I have separately calibrated them, and then merged the two uv files together using UVCAT prior to imaging.

I wanted to do a final bit of flagging with PGFLAG, so I set the new 'master' uv file (the one outputted from UVCAT) as the input and ran it. The problem is that once it has loaded up, data is visible only in the bottom half of the available PGFLAG window real estate - that is, data only appears for about half the times that the PGFLAG window has made room for. It would seem likely to me that PGFLAG is only showing/flagging data for one of the two uv files that were UVCATed together.

Does this sound like a plausible explanation for what I'm seeing? Can this be fixed, or does all flagging need to be done before UVCATing data from the different epochs together?

Cheers,

Craig.

[ste616]

Hi Craig,

This is an issue with the way pgflag reads in the data, as it expects that the data will be strictly in time order. In the past, pgflag would have exited if the records were out of order, but now it continues and displays what is in order.

The problem is that when you uvcat two sets together, the records are not rearranged to keep them in time order. If the two datasets that you are concatenating are really from two different epochs, then I suspect you may have specified them in the wrong order to uvcat.

Then again, this may be an entirely different issue. Let me know if this isn't your problem.

[and460]

Thanks Jamie - looks like I specified the UVCAT inputs from the two different epochs out of time order. I'll try it the other way around and see if it fixes the problem.

Thanks!